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28/APRIL/2020
MATHEMATICS
REVISION
As we know that 0,1,2,3,4,5,6,7,8,9 are 1 digit numbers and with the help of these ten numbers we can make 2 digit,3 digit and 4 digit numbers.
How to write the number in words:
a)345
First we have to write the numbers in place value like below:
HUNDREDS
|
TENS
|
ONES
|
3
|
4
|
5
|
Now expand the numbers below:
3hundreds=300
4tens=40
5ones=5
300+40+5
Therefore,345=Three hundred and forty-five
Assignment:
Write the following numbers in words:
a)205-Two hundred and five.
b)816-
c)999-
d)645-
e)718-
f)587-
g)369
Watch this video for better understanding.
29/APRIL/2020
MATHEMATICS
REVISION
How to write numbers in figures?
1)Eight hundred and twenty-five
First we have to write the numbers in place value:
HUNDREDS
|
TENS
|
ONES
| |
8
|
2
|
5
| |
Now expand the numbers below:
8 hundreds +2 tens + 5 ones
Therefore,800 +20+5=825
Assignment:
1) Seven hundred and seventy seven=777(example)
2) Two hundred seventy eight=
3) One hundred and nine=
4) Two hundred and forty nine=
5) Eight hundred and ten=
6) Three hundred and seventy five=
7) Nine hundred and seventy=
8) Nine hundred and ninety eight=
30/APRIL/2020
MATHEMATICS
REVISION
Write the following in short form:
Example: 600 + 30 + 9
Solution: 6 hundreds + 3 tens + 9 ones
= 639
Write the following in the expanded form:
Example: 785
Solution: 785 = 7 hundreds + 8 tens + 5 ones
= 700 + 80 + 5.
Assignment:
Ex-1: Write the following in short form:
1) 4 hundreds + 6 tens + 5 units=
2) 3 hundreds + 7 tens + 4 units=
3) 3 hundreds + 5 tens + 0 units=
4) 4 hundreds + 0 ten + 7 units=
Ex-2: Write the following in expanded form:
1) 369=
2) 719=
3) 850=
4) 993=
1/MAY/2020
MATHEMATICS
REVISION
Days of the week:
With the help of this picture, can you to write the day that comes after and before.
Example:
1)Friday comes after Thursday and before Saturday.
2) Tuesday comes after______ and before______.
3) Monday comes after ________ and before_______.
4) Thursday comes after________ and before________.
5) Wednesday comes after ________and before_________
6) Sunday comes after _______ and before_______.
7) Saturday comes after________and before_________.
Assignment:
With the help of the picture below draw the shapes. Name them (square, rectangle, triangle, cube, cuboid, cone, cylinder, circle, sphere).
2/MAY/2020
MATHEMATICS
REVISION
Chapter 2
(Numbers upto 10,000)
(Numbers upto 10,000)
Explanation:
Topic:1) Numbers upto 1000 and beyond 10,000.
We know that
10 ones make 1 ten
10 tens make 1 hundred
10 hundreds make 1 thousand
We write one thousand as 1000
1000 can be obtained by adding 1 to 999
999+1=1000
We observe that 999 is the greatest three digit number.
1000 is the smallest four digit number.
Numbers beyond 1000
1000+1=1001
By adding 1 we are able to get numbers beyond.
Therefore 9999+1=10,000
9999 is the greatest four digit number.
10,000 is the smallest five digit number.
Must watch this video for better understanding.
Assignment:
1) Write the smallest three-digit number.
100
2) Write the greatest three-digit number.
3) Write the smallest four-digit number.
4) Write the greatest four-digit number.
5) Write the smallest five-digit number.
4/MAY/2020
MATHEMATICS
Chapter 2
Place Value of 4-digit Numbers
The place value of a digit in a 4-digit number depends upon the position it occupies.
For example, the place value for 3-digit number 1489 will be, (see the picture below):
From the place value chart, we have:
The place value of 9 = 9 ones = 9
The place value of 8 = 8 tens = 80
The place value of 4 = 4 hundreds = 400
The place value of 1 = 1 thousand = 1000
Now watch this video...
Assignment:
Copy the exercises in your OCBs and complete them.
Fill in the blanks with the correct answer. The first one has been done for you.
Fill in the blanks with the correct answer. The first one has been done for you.
Exercise 1
a) 9 thousands 8 hundreds 7 tens and 6 ones = 9876
b) 6 thousand 4 hundreds 6 tens and 7 ones = _____
c) 8 thousands 7 hundreds 7 tens and 0 one = _____
d) 4 thousands 0 hundred 4 tens and 5 ones = _____
e) 8 thousands 0 hundred 8 tens and 6 ones = _____
Exercise 2
a) 9 ×1000 + 8 × 100 + 5 × 10 + 3 × 1 = 9853
b) 4 ×1000 + 2 × 100 + 4 × 10 + 6 × 1 = _____
c) 6 ×1000 + 2 × 100 + 3 × 10 + 7 × 1 = _____
d) 8 ×1000 + 0 × 100 + 4 × 10 +3 × 1 = _____
e) 7 × 1000 + 4 × 100 + 0 × 10 + 8 × 1 = _____
Exercise 3
a) The place value of 7 in 9721 is 700
b) The place value of 3 in 3462 is _____
c) The place value of 9 in 1903 is _____
d) The place value of 4 in 4023 is _____
e) The place value of 3 in 6432 is _____
5/MAY/2020
MATHEMATICS
Chapter 2
4-digit Number on an abacus
What is an abacus?
THESE ARE PICTURES OF TWO DIFFERENT TYPES OF ABACUS they however, do the same thing. One is vertical while the other is horizontal.
Now watch this video...
Example Exercise:
How to represent 4057 on an abacus?
4057 = 4 thousands + 0 hundred + 5 tens + 7 ones
The second spike from the right represents tens (T)
The third spike from the right represents hundreds (H)
The fourth spike from the right represents thousands (TH)
So we put 7 beads in ones place, 5 beads in tens place, 0 beads in the hundreds place and 4 beads in the thousands place.
Therefore,4057 = Four thousand fifty-seven
Now watch this video...
Assignment:
Copy the exercises in your OCBs and complete them. The first one in each exercise has been done for you.
Copy the exercises in your OCBs and complete them. The first one in each exercise has been done for you.
1. Write the following numerals in expanded form:
a) 2369 = 2000 + 300 + 60 + 9
b) 3709
c) 4044
d) 5555
e) 9097
2. Write the number names for the following:
a)8769 = Eight thousand seven hundred and sixty-nine.
a)8769 = Eight thousand seven hundred and sixty-nine.
b)2002
c)7391
d)4976
e)5067
3) Below we have represented 5728 on an Abacus now using the same example represent the following numbers on an Abacus in your OCBs. a) 7246
b)8297
c)3003
d)9760
e)2065
6/MAY/2020
MATHEMATICS
Chapter 2
Order Relation
Order Relation
1) Greater and Smaller number
2) Ascending and Descending order
Now watch this video...
Explanation:
A number having more digits is greater than having fewer digits.
If two numbers contain the same number of digits,we can compare them with the help of the digits on the extreme left. If this digit is the same in both the numbers, we compare the digits occupying the next place to its right and so on.
Example 1): Which is greater 2436 or 876?
Solution:2436 is a 4 digit number
876 is a 3 digit number
Therefore,2436>876
Example 2):which is greater 6725 or 3897
Solution:6725 has 6 thousand
3897 has 3 thousand
Therefore,6725> 3897
Therefore,6725> 3897
Ascending order (smaller number to the greater number)
Descending order (greater number to the smaller number)
Now watch this video...
Assignment:
Copy the Place Value Worksheet into your OCB exercise book and complete it.
7/MAY/2020
MATHEMATICS
Chapter 2
Ascending and Descending Order
Ascending order: Arranging numbers in increasing order (smallest to the greatest)
Descending order: Arranging numbers in decreasing order (greatest to the smallest)
Now watch this video...
Assignment:
1) Rewrite the following numbers in ascending order:(The first one is done for you)
a)
|
726
|
762
|
7762
|
5656
|
4343
|
8989
|
99
|
Ans
|
99
|
726
|
762
|
4343
|
5756
|
7762
|
8989
|
b)
|
9909
|
9099
|
9999
|
9009
|
9990
|
999
|
9000
|
Ans
| |||||||
c)
|
74
|
123
|
1865
|
783
|
2356
|
1987
|
98
|
Ans
| |||||||
d)
|
8337
|
8373
|
8377
|
8737
|
8733
|
5642
|
8333
|
Ans
| |||||||
e)
|
5762
|
963
|
639
|
6326
|
2673
|
396
|
5757
|
Ans
|
2) Rewrite the following numbers in descending order:(The first one is done for you)
a)
|
6754
|
5235
|
9801
|
6765
|
786
|
856
|
96
|
Ans
|
9801
|
6765
|
6754
|
5235
|
856
|
786
|
96
|
b)
|
3562
|
4029
|
3586
|
86
|
866
|
752
|
7351
|
Ans
| |||||||
c)
|
8000
|
6000
|
600
|
789
|
7891
|
99
|
5333
|
Ans
| |||||||
d)
|
1234
|
1046
|
2986
|
756
|
987
|
8035
|
8305
|
Ans
| |||||||
e)
|
9586
|
98
|
991
|
7603
|
5654
|
783
|
8462
|
Ans
|
8/MAY/2020
MATHEMATICS
Chapter 2
Successor and predecessor number:
The number that comes just after a particular number is called its successor. The successor of a number is 1 more than the number.
The number that comes just before a particular number is called its predecessor. The predecessor of a number is 1 less than the number
Watch this video for a better understanding
https://youtu.be/hSPuznfdWtk
Assignment:
1) write the successor of each of the following:
a)2999=3000
b)1005 =
c)3959 =
d)9999 =
e)7699=
f)3101=
2) write the predecessor of each of the following:
a)498=499
b)_____768
c_____ 599
d)_____3999
e)______8610
f)______1000
3)Fill in the blanks:
a)The successor of a number is one_______than the number.
b) The predecessor of a number is one ______ than the number.
c) The successor of 0 is_______.
d) The predecessor of 99 is_______.
9/MAY/2020
MATHEMATICS
Chapter 2
Skip counting
If starting with a given number we write some numbers with a fixed gap between two successive numbers, then such counting is called skip counting.
Skip counting by twos means that there is a gap of 2 in every successive number.
Skip counting by fives means that there is a gap of 5 in every successive number.
Skip counting by tens means that there is a gap of 10 in every successive number.
Skip counting by hundreds means that there is a gap of 100 in every successive number.
Now watch this video...
Assignment
Complete this exercises in your OCB'S book.(The first one of each exercise has been done for you.)
1) Counting by twos, write the numbers from:
| |||||||
a).
|
5155
|
to
|
5167
| ||||
Ans
|
5155
|
5157
|
5159
|
5161
|
5163
|
5165
|
5167
|
b)
|
9320
|
to
|
9332
| ||||
Ans
| |||||||
c)
|
1096
|
to
|
1108
| ||||
Ans
| |||||||
d)
|
1500
|
to
|
1512
| ||||
Ans
| |||||||
e)
|
1550
|
to
|
1562
| ||||
Ans
| |||||||
2) Counting by tens, write the numbers from:
| |||||||
a
|
3880
|
to
|
3940
| ||||
Ans
|
3880
|
3890
|
3900
|
3910
|
3920
|
3930
|
3940
|
b)
|
4886
|
to
|
4946
| ||||
Ans
| |||||||
c)
|
6993
|
to
|
7063
| ||||
Ans
| |||||||
d)
|
7890
|
to
|
8050
| ||||
Ans
| |||||||
e)
|
8891
|
to
|
9051
| ||||
Ans
| |||||||
3) Counting by hundreds, write the numbers from:
| |||||||
a
|
4202
|
to
|
4802
| ||||
Ans
|
4202
|
4302
|
4402
|
4502
|
4602
|
4702
|
4802
|
b)
|
1082
|
to
|
1682
| ||||
Ans
| |||||||
c)
|
6801
|
to
|
7401
| ||||
Ans
| |||||||
d)
|
6999
|
to
|
7599
| ||||
Ans
| |||||||
e)
|
5715
|
to
|
6315
| ||||
Ans
| |||||||
4) Look at the pattern and fill in the blanks:
| |||||||
a
|
1235
|
1238
|
1241
| ||||
Ans
|
1244
|
1247
|
1250
|
1253
|
1256
|
1259
|
1262
|
b)
|
6372
|
6377
|
6382
| ||||
Ans
| |||||||
c)
|
8272
|
8282
|
8292
| ||||
Ans
| |||||||
d)
|
6397
|
6497
|
6597
| ||||
Ans
| |||||||
e)
|
9815
|
8815
|
7815
| ||||
Ans
| |||||||
11/MAY/2020
MATHEMATICS
Chapter 3 ADDITION:
In the previous class, we learnt how to add two or more numbers of one, two or three digits.The same method is applied when we add 4 digit numbers.
Sign of addition= (+)
Now watch this video....
When some numbers are added,each one of the numbers to be added is called an addend.The final result obtained after addition is called their sum
ADDITION WITHOUT CARRYING OVER
Method: For adding two or more numbers, we take the following steps:
Step 1: Arrange the digits of the given numbers in columns of thousands (Th), hundreds (H), tens((T) and ones(O).
Step 2: Add column wise
Add the ones, add the tens, add the hundreds and add the thousands.
See the following example:
See the following example:
Add 3564 and 4123
Solution: we arrange the given numbers in columns with headings.
Calculation:
Th H T O
3 5 6 4--------( 1st addend)
+ 4 1 2 3--------( 2nd addend)
-----------------------------------
7 6 8 7-------------(sum)
--------------------------------------
Now watch this video....
Explanation:
Explanation:
Step 1: we add corresponding ones:
4 ones + 3 ones = 7 ones
Write 7 under one's column
Step 2: we add corresponding tens
6 tens + 2 tens = 8 tens.
Write 8 under tens column.
Step 3: we add corresponding hundreds
5 hundreds + 1 hundred= 6 hundreds
Write 6 under hundreds column
Step 4 : we add corresponding thousands
3 thousands + 4 thousands= 7 thousands
Write 7 under thousands column
Sum: 3564 + 4123 = 7687
Assignment
Ex-1 (Complete this worksheet in your OCBs)
Ex-2. Arrange in columns and add:
a) 7432 and 1350
b) 4321 and 2678
c) 5132 and 2645
d) 3046 and 6250
12/MAY/2020
MATHEMATICS
Chapter 3 ADDITION WITH CARRYING:
Now watch this video...
Example: Add 4378 and 5485
Solution: We arrange the given numbers in columns with headings (thousands) Th,
(hundreds) H, (tens) T and (ones) O
Adding column wise , we get:
Explanation:
Step 1: Add corresponding ones:
8 ones +5 ones = 13 ones
= 1 ten + 3 ones.
So, we write 3 in one's column in the answer and carry 1 to tens column.
We shall add this 1 ten along with the tens.
Step 2: Add corresponding tens:
1 ten ( which we carried from step 1)+ 7 tens 8 tens = 16 tens.
= 10 tens + 6 tens = 1 hundred + 6 tens
So, we write 6 in tens column in the answer and carry 1 to hundreds columns
We shall add this 1 hundred along with the hundreds.
Step 3: Add corresponding hundreds:
1 hundred ( which we carried from step 2) + 3 hundreds + 4 hundreds = 8 hundreds.
So, we write 8 in hundreds column in the answer.
Step 4: Add corresponding thousands:
4 thousands + 5 thousands =
9 thousands
So, we write 9 in thousands column in the answer.
Calculation:
Th
|
H
|
T
|
O
| ||
1
|
1
|
------CARRY OVER
| |||
4
|
3
|
7
|
8
| ||
+
|
5
|
4
|
8
|
5
| |
9
|
8
|
6
|
3
|
-------SUM
|
Therefore, sum: 4378 + 5485 = 9863
Example 2: Find the sum:
3954 + 2737 + 493 + 86
Solution: We arrange the given numbers in columns and add them.
Th
|
H
|
T
|
O
| ||
2
|
2
|
2
|
------CARRY OVER
| ||
3
|
9
|
5
|
4
| ||
2
|
7
|
3
|
7
| ||
4
|
9
|
3
| |||
+
|
8
|
6
| |||
7
|
2
|
7
|
0
|
-------SUM
|
Therefore, 3954+2737+493+86= 7270.
Assignment
Complete this exercises in your OCB exercise book.
Ex-1:
Ex-2: Find the sum: (see the example above)
a) 6999+ 998 +89
b) 3805+ 3986+ 732
c) 8725+ 682+ 361
d) 5312+ 2280+ 857+ 921
13/MAY/2020
MATHEMATICS
Chapter 3 Properties of addition
There are three properties of addition
1) Order property for addition
2) Grouping property for addition
3) Additive property of zero.
Now watch the video...
1) Order property: The sum of two numbers is independent of the order in which the numbers are arranged for addition.
Example:
4378+3764 = 3764+4378
4378+3764 = 3764+4378
8142 8142
Thus, the sum of two numbers does not change when the order of the addends are changed.
2) Grouping property: The sum of three numbers is the same even if the grouping of the numbers are changed.
Example:
(1265 + 2369) + 3017
(1265 + 2369) + 3017
=3661 + 3017
=6678
Also.
1265 + (2396 + 3017)
1265 + (2396 + 3017)
=1265 + 5413
=6678
Thus, the sum of three numbers is the same even if the grouping of the numbers are changed.
3) Additive property of zero: The sum of a number and 0 is the number itself.
Example:
2684 + 0 = 2684
2684 + 0 = 2684
0 + 2684 = 2684
Thus, the sum of a number and '0' is the number itself.
With the help of the examples above copy and complete this exercise in your OCB exercise book.
Fill in the blanks:
a. 3275 + 1768 = 1768 + ________.
b. 6498 + 1381 = 1381 +_________.
c. ________ + 2654 = 2654 + 1987
d. 2001 + _______ = 1999 + 2001
e. 0 + _________ = 2357 + 0
f. 7981 + _______ = 7981
g. (1368 + 2452) + 1073 = ________ + (2452 + 1073)
h. (1798 + 3265) + 2678 = 1798 + (3265 +________).
i. (2165 + 3978) + 459 =_________ + (3978 + 459)
j. (2375 + 1625) +_________ = 2375 + (1625 + 1955).
14/MAY/2020
MATHEMATICS
Chapter 3
Word problems on addition:
Now watch this video...
Words which can be used for addition are add, plus, sum, in all, altogether, total, all , increase, more than.
Example:
There are 2089 bags of wheat, 896 bags of rice and 4737 bags of sugar in a store. Find the total number of bags in the store?
Solution:
Number of bags of wheat
|
=
|
2089
| ||
Number of bags of rice
|
=
|
896
| ||
Number of bags of sugar
|
=
|
4737
| ||
Total number of bags
|
=
|
2089 + 896 + 4737
|
=
|
7722
|
Answer: Hence, the total number of bags in the store is 7722
Complete this exercise in your OCB-MATHS Ex-Book
1) Ram purchased a washing machine for Rs 5468 and a geyser for Rs 3646 from a shop.How much money does he have to pay for both the articles?
2) A factory produces 5375 and 1987 bulbs in two days. How many bulbs are produced altogether in two days?
3) The difference between two numbers is 1876. If the smaller number is 7948, find the larger number.
4) A fruit seller has 4583 bananas, 2836 oranges and 1204 pineapples in his shop.How many fruits does he have in his shop?
5) There are 3583 men, 2809 women and 1385 children in a town. What is the population of this town?
15/MAY/2020
MATHEMATICS
Chapter 3 Word problems on addition:
Assignment
Complete this exercise in your OCB-Mathematics exercise book.
(The first one has been done for you.)
(The first one has been done for you.)
1) Amit collected 6390 stamps in one album and 3539 stamps in another album. How many stamps did Amit collect in all?
Number of stamps in the first album
|
=
|
6390
| |
Number of stamps in the second album
|
=
|
3539
| |
Total number of stamps
|
=
|
6390 + 3539
| |
Hence, the total number of stamps collected by
|
Amit
|
is =
|
9929
|
Calculation
| |||
Number of stamps in the first album
|
=
|
6 3 9 0
| |
Number of stamps in the second album
|
=
|
3 5 3 9
| |
Total number of stamps
|
=
|
9 9 2 9
| |
Hence, the total number of stamps collected by Amit is 9929
| |||
2) A farmer produced 6813 kg, 2036 kg and1092 kg of wheat, barley and rice respectively in 2001. What was his total production in 2001?
3) A factory makes 2383, 4809, 1854 bottles in three days. How many bottles does the factory make in these days?
4) A soap factory produced 3948, 2879 and 2507 soap cakes in three days.How many soap cakes were produced in all?
16/MAY/2020
MATHEMATICS
Chapter 4 SUBTRACTION
Subtraction is an arithmetic operation that represents the operation of removing objects from a collection.The result of a subtraction is called a difference. Subtraction is signified by the minus sign ( - ).
Now watch the video...
Method:
For subtracting a number from another number we take the following steps.
Step 1: write the smaller number under the larger number in columns
Step 2: subtract column-wise.
Subtract ones from ones, tens from tens, hundreds from hundreds and thousands from thousands.
Subtract ones from ones, tens from tens, hundreds from hundreds and thousands from thousands.
SUBTRACTION WITHOUT BORROWING:
Example:
Subtract 3462 from 7586
Explanation and Solution:
First arrange the given numbers in columns of thousands (Th), hundreds (H), tens(T) and ones (O) as follows;-
Th
|
H
|
T
|
O
| |
7
|
5
|
8
|
6
| |
-
|
3
|
4
|
6
|
2
|
Step 1: We subtract corresponding ones
6 ones - 2 ones = 4 ones
Step 2: we subtract corresponding tens
8 tens - 6 tens = 2 tens
Step 3: we subtract corresponding hundreds
5 hundreds -4 hundreds = 1 hundred
Step 4: we subtract corresponding thousands
7 thousands - 3 thousands = 4 thousands
Therefore ,7586 - 3462 = 4124
Therefore ,7586 - 3462 = 4124
Calculation:
Th
|
H
|
T
|
O
| |
7
|
5
|
8
|
6
| |
-
|
3
|
4
|
6
|
2
|
4
|
1
|
2
|
4
|
Assignment
Complete the following exercise on Subtraction in your OCB-Mathematics exercise book.
1) Subtract 6501 from 8931
2) Subtract 3650 from 6666
3) Subtract 3333 from 4444
4) Subtract 6510 from 7641
5) Complete the subtraction exercise below-
18/MAY/2020
MATHEMATICS
Chapter 4 SUBTRACTION
SUBTRACTION WITH BORROWING:
Now watch this video...
Assignment
Complete this exercise in your OCB Mathematics exercise book.
19/MAY/2020
MATHEMATICS
Chapter 4 SUBTRACTION
SUBTRACTION WITH BORROWING ACROSS ZEROS
Now watch this video:
Example:
Subtract 4653 from 8400
Solution:
First arrange the given numbers in columns of thousands (Th), hundreds (H), tens(T) and ones (O) as follows;-
Calculation:
Th
|
H
|
T
|
O
| |
8
|
4
|
0
|
0
| |
-
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4
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6
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5
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3
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3
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7
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4
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7
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Explanation:
Step1: We subtract corresponding ones. We want to subtract 3 from 0. But 3 > 0. So, we borrow 1 from tens place. But, there is 0 at tens place. So, we borrow 1 hundred, leaving behind 3 hundreds.
Now, 1 hundred = 10 tens = 9 tens + 1 ten = 9 tens + 10 ones.
Now, we have 3 at hundreds place, 9 at tens place and 10 at ones place.
Now, 10 ones - 3 ones = 7 ones
Step 2: We subtract corresponding tens
9 tens - 5 tens = 4 tens.
Step 3: We subtract corresponding hundreds. We want to subtract 6 from 3. But 6 > 3. So, we borrow 1 thousand, leaving behind 7 thousands. And, 1 thousand +3 hundreds = 13 hundreds
13 hundreds - 6 hundreds = 7 hundreds.
Step 4: We subtract corresponding thousands. 7 thousands - 4 thousands = 3 thousands.
Therefore, 8400 - 4653 = 3747.
Assignment
Complete this exercise in your OCB Mathematics exercise book.
20/MAY/2020
MATHEMATICS
Chapter 4 SUBTRACTION
Word problems on Subtraction:
Assignment
Complete this exercise in your OCB-Mathematics exercise book. The first one has been done for you as an example of how to do it.
1) Ram earned Rs 6976 in May and spent Rs 4896. How much money did he save?
Solution:
Ram earned in May
|
=
|
Rs 6976
| ||||
Ram spent
|
=
|
Rs 4896
| ||||
Therefore, Ram saved
|
=
|
Rs 6976
|
-
|
Rs 4896
|
=
|
Rs 2080
|
2) A carpenter had 6530 nails. He used 4849 of them. How many nails were left?
3) There are 3250 students in a school. If 1867 of them are boys, how many girls are there?
4) The sum of two numbers is 9806. If one of the numbers is 6938, find the other number.
5)There are 3800 seats in a theater. On Monday 2739 persons saw the show. How many seats remained vacant?
21/MAY/2020
MATHEMATICS
Chapter 4 Word problems on Subtraction:
Assignment
Complete this exercise in your OCB-Mathematics exercise book. The first one has been done for you as an example of how to do it.
1) What number must be added to 4817 to get 6000?
Solution:
Sum of the two numbers
|
=
|
6000
| ||||
One of the numbers
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=
|
4817
| ||||
Therefore, the other number
|
=
|
6000
|
-
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4817
|
=
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1183
|
Hence, 1183 must be added to 4817 to get 6000.
2) The difference between two numbers is 2895. If the larger number is 8560, find the smaller one.
3) Subtract the difference of 8312 and 789 from their sum.
4) The sum of two numbers is 9864. If one of them is 4976, find the other.
5) There are 2350 students in a school. If the number of boys is 1285, how many girls are there?
22/MAY/2020
MATHEMATICS
Chapter 4 SUBTRACTION
Combined operation of Addition and Subtraction
Now watch this video:
Explanation:
If in a problem there are three or more numbers given, we solve it in the following steps:
Step 1- Add all the numbers which have + or no sign before them.
Step2- Add all the numbers which have - sign before them.
Step 3- Subtract the second sum obtained in step 2 from the first sum obtained step 1.
Example:
6428 - 3369 + 1614 - 2608
6428 - 3369 + 1614 - 2608
Solution:
First add numbers with '+' sign or no sign before them.
6 4 2 8
+ 1 6 1 4
8 0 4 2
Adding numbers with ' - ' sign before them.
3 3 6 9
+ 2 6 0 8
3 3 6 9
+ 2 6 0 8
5 9 7 7
Now Subtract the second sum from the first sum.
8 0 4 2
- 5 9 7 7
2 0 6 5
Hence, 6428 - 3369 + 1614 - 2608 = 2065.
Assignment
Complete this exercise in your OCB-Mathematics exercise book.
Simplify the following:
1) 8214 - 4256 + 9524 + 5412
2) 6465 - 6734 - 1540 + 2319
1) 8214 - 4256 + 9524 + 5412
2) 6465 - 6734 - 1540 + 2319
3) 7300 - 3450 - 769 - 1497
4) 5825 - 1376 + 574 - 2809
5) 7643 + 1465 - 2369 - 999.
23/MAY/2020
MATHEMATICS
Chapter 4 SUBTRACTION
Word problem on combined operation of addition and subtraction
Now watch this video:
Assignment
Complete this exercise in your OCB Mathematics exercise book. The first one has been done for you.
1) There are 6039 toys in a store. 1708 toys are sold on Monday,1359 toys are sold on Tuesday. How many toys are left in the store?
Solution:
Total Number of Toys in the store
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=
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6039
| ||||
Number of toys sold on Monday
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=
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1708
| ||||
Number of toys sold on Tuesday
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=
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1359
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Total number of toys sold on both days
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=
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1708
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+
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1359
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=
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3067
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The number of toys left in the store
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=
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6039
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-
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3067
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=
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2972
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Hence, 2972 toys are left in the store.
| ||||||
2) There are 7000 exercise books in a school book shop. If it sold 3510 and 2892 exercise books in two days, how many exercise books were left in the book shop.
3) The population of a town is 8215. If there are 3438 men and 2859 women, how many children are there in the town.
4) The sum of three numbers is 9010. If two of them are 3768 and 1697, find the third number.
5) Sumeet has Rs 9672 in his purse. Amit has Rs 8769 in his purse. Who has more money and by how much?
26/MAY/2020
MATHEMATICS
Chapter 5: MULTIPLICATION
The sign of multiplication is X meaning 'into'
CHECK THIS OUT
Now watch this video...
Assignment
Complete this exercise in your Mathematics-OCB.
Ex.1 Fill in the blanks. The first one has been done for you.
a)
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6 X 9 =
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54
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b)
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5 X 8 =
| |
c)
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7 X 6 =
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d)
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3 X 8 =
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e)
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8 X 6 =
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f)
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4 X 7 =
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g)
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9 X 9 =
|
Ex.2 Recite and memorize the tables of 2, 4 and 8.(ALOUD)
27/MAY/2020
MATHEMATICS
Chapter 5 MULTIPLICATION
Assignment
Complete this exercise in your Mathematics-OCB. The first one has been done for you.
Ex.1 Fill in the blanks.
a) 6 X 19 = 114
b) 5 X 18 = ___
c) 7 X 16 = ___
d) 3 X 18 = ___
e) 4 X 12 = ___
f) 9 X 19 = ___
g) 8 X 12 = ___
h) 9 X 15 = ___
i) 7 X 19 = ___
j) 6 X 15 = ___
b) 5 X 18 = ___
c) 7 X 16 = ___
d) 3 X 18 = ___
e) 4 X 12 = ___
f) 9 X 19 = ___
g) 8 X 12 = ___
h) 9 X 15 = ___
i) 7 X 19 = ___
j) 6 X 15 = ___
Ex.2 Recite and memorize the tables of 3, 6 and 12. (ALOUD)
28/MAY/2020
MATHEMATICS
Chapter 5 MULTIPLICATION
Problems relating multiplication tables
Multiplication word problems can be framed using different terms like number of times as many, multiplied by, in all, altogether etc.
Now watch this video:
Assignment
Complete this exercise in your OCB Mathematics exercise book. The first one has been done for you.
1) The gardener has planted 9 trees in a row. How many trees has he planted in 11 rows?
Solution:
Number of trees planted in 1 row = 9
Number of trees planted in 11 rows
= 9 X 11 = 99 trees.
Therefore,he has planted 99 trees in 11 rows.
2) There are 16 students in a class. How many exercise books will be distributed among them if each boy gets 4 exercise books?
3) Subhash reads 7 hours a day. How many hours does he read in 17 days?
4)There are 12 articles in a dozen. How many articles will there be in 6 dozens?
5) There are 12 bananas in each bunch How many bananas will there be in 9 bunches?
Ex-2 Recite and memorize the tables of 5, 10 and 15.(ALOUD)
29/MAY/2020
MATHEMATICS
Chapter 5 MULTIPLICATION
Problems relating multiplication tables
Assignment
Complete this exercise in your OCB Mathematics exercise book. The first one has been done for you.
Ex-1) 1). There are 14 questions in each exercise. How many questions will there be in 8 exercises?
Solution:
Number of questions in 1 exercise = 14
Number of questions in 8 exercises
14 X 8 = 112
Therefore, 112 questions will be there in 8 exercises.
2) A pencil costs Rs 7 . How much will 19 such pencils cost?
3) Neha needs 13 balls of wool to make sweater. How many balls will she require to make 7 sweaters?
4) There are 18 balls in a bag. How many balls are there in 5 such bags?
5) A man travels 8 km daily. How much distance will he travel in 19 days?
Ex-2 Recite and memorize the tables of 7, 14.(ALOUD)
30/MAY/2020
MATHEMATICS
Chapter 5 MULTIPLICATION
Tables of 9 ,11 and 13
Complete this exercise in your Mathematics-OCB. The first one has been done for you.
Ex-1) Fill in the blanks:
a
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8
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X
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11
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=
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88
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b
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X
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13
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=
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117
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c
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X
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13
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=
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104
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d
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9
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X
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15
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=
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e
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11
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X
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10
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=
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f
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8
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X
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13
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=
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g
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11
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X
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5
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=
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Ex-2) Recite and memorize the tables of 9, 11 and 13.(ALOUD)
Now watch this video.
Assignment
The following facts about multiplication:
Multiplication by one digit number without carrying
1/JUNE/2020
MATHEMATICS
Chapter 5 MULTIPLICATION
Multiplication tables
Tables of 16 ,17 and 18
Multiplication tables
Tables of 16 ,17 and 18
Assignment
Complete this exercise in your Mathematics-OCB.
Ex-1) Fill in the blanks:
a
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16
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X
| 2 |
=
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b
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X
| 5 |
=
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c
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X
| 4 |
=
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d
| 17 |
X
| 9 |
=
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e
| 18 |
X
| 3 |
=
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f
| 18 |
X
| 8 |
=
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g
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18
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X
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5
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=
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Ex-2) Recite and memorize the tables of 16, 17 and 18. (ALOUD)
2/JUNE/2020
MATHEMATICS
Chapter 5 MULTIPLICATION
Multiplication tables
Tables of 19 and 20
Complete this exercise in your Mathematics-OCB.
Ex.1 Complete the exercise to understand what multiplication is all about.
Ex.2 Recite and memorize the tables of 19 and 20.(ALOUD)
Ex.1 Complete the exercise to understand what multiplication is all about.
3/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Multiplication of numbers
1) Multiplication is a repeated addition.
2) The number to be multiplied is called multiplicand.
3) The number by which we multiply is called multiplier.
4) The answer or the result of the Multiplication is called product.
Example:
9
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X
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3
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=
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27
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Multiplicand
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Multiplier
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Product
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Multiplication by one digit number without carrying
Now watch this video.
Explanation:
Multiply 212 by 4
Solution:
Arrange the given numbers in columns
1) Multiply each place in turn by 4, starting with the one's column.
2) 2 X 4 = 8 ones.Write 8 in the one's column.
3) 1 X 4 = 4 tens . Write 4 in the tens column.
4) 2 X 4 = 8 hundreds.Write 8 in the hundreds column.
Calculation:
Hence, 212 X 4 = 848
H
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T
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O
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2
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1
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2
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X
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4
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8
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4
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8
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Product = 848
Assignment
Complete this exercise in your Mathematics - OCB. The first one has been done for you
Ex1- Multiply the following:
a) 4 3 2 X 2
H
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T
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O
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4
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3
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2
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X
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2
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8
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6
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4
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b) 2 1 2 X 3
c) 2 2 1 X 4
d) 4 1 2 3 X 2
e) 3 2 3 1 X 3
f) 2 2 2 2 X 4
d) 1397 X 6
e) 1453 X 4
f) 4327 X 2
4/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Multiplication of numbers:
Multiplication by 1 digit number with carrying.
Now watch this video
Explanation:
Multiply 1346 by 6
Solution:
Arrange the given numbers in place value columns as shown below.
Therefore, 1346 X 6 = 8076
Th
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H
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T
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O
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2
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2
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3
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è Carry over digits
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1
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3
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4
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6
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è Multiplicand
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X
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6
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è Multiplier
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8
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0
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7
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6
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è Product
|
Therefore, 1346 X 6 = 8076
Assignment
Complete this exercise in your Mathematics -OCB.
Ex 1-Multiply the following.
1)
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H
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T
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O
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2)
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H
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T
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O
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3)
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H
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T
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O
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4)
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H
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T
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O
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2
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5
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6
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6
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3
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3
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1
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0
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4
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8
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1
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5
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x
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6
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x
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2
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x
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9
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x
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3
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5)
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H
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T
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O
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6)
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H
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T
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O
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7)
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H
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T
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O
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8)
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H
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T
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O
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8
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6
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3
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3
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9
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8
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2
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0
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7
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7
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1
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5
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x
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7
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x
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5
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x
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5
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x
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7
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9)
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H
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T
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O
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10)
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H
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T
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O
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11)
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H
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T
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O
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12)
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H
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T
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O
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8
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1
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3
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6
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5
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8
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6
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6
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0
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4
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8
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5
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x
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4
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x
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2
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x
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3
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x
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9
| ||||||||
5/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Multiplication by single digit numbers with carrying.
Assignment: Complete all exercises in your Mathematics-OCB.
Ex 1-Multiply the following.
1)
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H
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T
|
O
|
2)
|
H
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T
|
O
|
3)
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H
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T
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O
|
4)
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H
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T
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O
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5
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8
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6
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6
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6
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8
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3
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1
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8
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5
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1
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7
| ||||
x
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2
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x
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3
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x
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4
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x
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5
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5)
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H
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T
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O
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6)
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H
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T
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O
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7)
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H
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T
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O
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8)
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H
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T
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O
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1
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5
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8
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8
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6
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9
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2
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8
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7
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7
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5
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1
| ||||
x
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6
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x
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7
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x
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8
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x
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7
| ||||||||
9)
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H
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T
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O
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10)
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H
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T
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O
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11)
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H
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T
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O
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12)
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H
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T
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O
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7
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4
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2
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6
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3
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6
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4
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2
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6
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8
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5
|
3
| ||||
x
|
7
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x
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6
|
x
|
9
|
x
|
3
| ||||||||
6/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Assignment: Complete all exercises in your Mathematics-OCB.
Complete the exercise by Multiplying a number by a single digit with carrying. The first one has been done for you.
Ex-1. Find the product:
c) 5346 X 6
a) 874 X 4
Solution:
Solution:
H
|
T
|
O
| |||||||||||||
8
|
7
|
4
| |||||||||||||
X
|
4
| ||||||||||||||
3
|
4
|
9
|
6
| ||||||||||||
b) 963 X 5
d) 1397 X 6
e) 1453 X 4
f) 4327 X 2
8/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Multiplication by 10, 100 and 1000
Multiplication by 10, 100 and 1000
Rules : To multiply a given number by 10, or 100 or 1000, we put one, two or three zeroes respectively to the right of the given number and we get the product.
Now watch this video
Multiplication by 10, 20 ,30 ,40 ..........., 90
We know that when we multiply a number by 10. We insert one zero on the right of the number to get the product.
Multiply 643 by 10
Solution:
643 X 10 = 643 X 1 ten = 643 tens = 6430
Multiply 14 by 30
Solution:
We know that 30 = 3 X 10 = 3 tens
14 X 30 = 14 X 3 tens = 42 tens = 420
Multiply 12 by 50
Solution:
We know that 50 = 5 X 10 = 5 tens
12 X 50 = 12 X 5 tens = 60 tens = 600
Multiply 9 by 90
Solution:
We know that 90 = 9 X 10 = 9 tens
9 X 90 = 9 X 9 tens = 81 tens = 810.
Conclusion: To multiply a given number by 20, 30, 40 ,........, 90, we multiply the given number by 2, 3, 4 ,........, 9 respectively and put a zero to the right of the product.
Assignment: Complete all exercises in your Mathematics-OCB.
Complete this exercise in your Mathematics -OCB.
Ex-1) Multiply the following:
Ex-1) Multiply the following:
a) 29 X 10
|
b) 415 X 10
|
c) 43 X 20
|
d) 16 X 20
|
e) 46 X 30
|
f) 52 X 30
|
g) 27 X 40
|
h) 73 X 40
|
i) 14 X 50
|
9/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Multiplication by 100, 200, 300, 400.......900
We know that when we multiply a number by 100.We put two zeroes on the right of the number to get the product.
To multiply a given number by 200, 300 ,400, ........., 900, we multiply the given number by 2, 3, 4,........,9 respectively and put two zeroes to the right of the product.
Example: Multiply 16 by 400
Solution:
We know that 400= 4 X 100 = 4 hundreds
Therefore, 16 X 400 = 16 X 4 hundreds
= 64 hundreds = 6400.
Assignment: Complete the following in your Mathematics-OCB.
Mathematics Book, Pg. No. 69, Ex. No. 6B, Do no. 25 to 40.
Four of them have been done for you.
Four of them have been done for you.
25) 80 X 80
We know that 80 = 8 X 10= 8 tens
Therefore, 80 X 80 =( 80 X 8 )tens
= 640 tens = 6400.
29) 37 X 700
We know that 700 = 7 X 100 = 7 hundreds
Therefore, 37 X 700 =( 37 X 7 ) hundreds
= 259 hundreds = 25900.
36) 4 X 3 X 600
12 X 600
We know that 600 = 6 X 100 = 6 hundreds
Therefore, 12 X 600 = ( 12 X 6) hundreds
= 72 hundreds = 7200.
39 ) 10 X 12 X 30
120 X 30
We know that 30 = 3 X 10 = 3 tens
Therefore, 120 X 30 = ( 120X 3) tens
= 360 tens = 3600.
10/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg. No. 69, Ex. No. 6B, Do nos. 41 to 52.
Three of them have been done for you
41) 68 X 800
We know that 800 = 8 X 100 = 8 hundreds
Therefore, 68 X 800 = (68 X 8) hundreds
= 544 hundreds = 54400
46) 18 X 4 X 100
72 X 100 = ( 72 X 1) hundreds
= 72 hundreds = 7200.
51) 45 X 15 X 10
675 X 10 = ( 675 X 1 ) tens
= 675 tens = 6750.
11/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Now watch this video.
Properties of Multiplication
1) ORDER PROPERTY:
If we multiply two numbers in any order, the product remains the same. This is known as order property of multiplication of numbers.
For example:
4 X 2 = 8 and 2 X 4 = 8
Therefore, 4 X 2 = 2 X 4 = 8
2) GROUPING PROPERTY:
The product of three numbers remains the same even when the grouping of the number is changed.
For example:
( 5 x 6) X 3 = 30 X 3 = 90 and
5 x ( 6 X 3 ) = 5 x 18 = 90
Therefore, (5 x 6) X 3 = 5 x ( 6 X 3) = 90
It means that the product of numbers 5, 6 and 3 in different order is same.
3) MULTIPLICATIVE PROPERTY OF 1:
The product of any number and 1 is the number itself.
9 c 1 = 9, 6 X 1 = 6
4) MULTIPLICATIVE PROPERTY OF ZERO:
The product of any number and 0 is zero.
8 X 0 = 0, 136 X 0 = 0
5) DISTRIBUTIVE PROPERTY OF MULTIPLICATION OVER ADDITION:
First number X( second number + third number) = ( First number X second number) + ( First number X third number)
5 x (4 + 3) and ( 5 x 3) + ( 5 x 3)
Solution:
5 x ( 4 + 3) = 5 x 7 = 35
Also, ( 5 x 4) + ( 5 x 3) = 20 + 15 = 35
Thus, 5 x (4 + 3 ) = ( 5 x 4) + ( 5 x 3)
Assignment: Complete all exercises in your Mathematics-OCB.
Mathematics book, Pg.No. 70 and 71, Ex . No. 6C ,Do No. 1 to 25.
Five of them have been done for you.
1) 15 X 38 = 38 X 15
5) 65 X 35 = 35 X 65
10) 96 X 0 = 0
16) 9 X ( 7 X 6 ) = ( 9 X 7 ) X 6
24) 5 x ( 40 + 7 ) = ( 5 x 40 ) + ( 5 x 7 ).
12/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Multiplication of two digit number by using the properties of multiplication.
Example:
Multiply 77 X 35
Solution:
77 X 35 = 77 X ( 30 + 5) = ( 77 X 30) +(77 X 5)
= 2310 + 385 = 2695
Hence, 77 X 35 = 2695.
Assignment: Complete all exercises in your Mathematics-OCB.
Mathematics book , Pg. No. 72 , Ex. 6D ,Do No. 1 to 8.
Two of them have been done for you.
1) 47 X 31
47 X 31 = 47 X ( 30 + 1) = (47 X 30) + (47 X 1)
= 1410 + 47 = 1457.
6) 88 X 105
88 X 105 = 88 X ( 100 + 5)
= ( 88 X 100) + ( 88 X 5 )
= 8800 + 440 = 9240.
13/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Example
NOW WATCH THE VIDEO.
Assignment: Complete all exercises in your Mathematics-OCB.
Mathematics book, Do No. 9 to 20 Pg. No. 73, Ex. No. 6D
Three of them have been done for you.
9) Th H T O
1 3 5
X 6 4
5 4 0
8 1 0 X
8, 6 4 0
15) Th H T O
3 7 4
X 2 8
2 9 9 2
7 4 8 X
10, 4 7 2
19) Th H T O
7 1 9
X 1 9
6 4 7 1
7 1 9 X
13, 6 6 1
15/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Word problems on Multiplication
NOW WATCH THE VIDEO.
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book,do No's.1 to 10. Pg No.74, Ex. No. 6E
Three of them have been done for you.
1) There are 62 oranges in one basket. How many oranges will there be in 60 baskets?
Number of oranges in 1 basket = 62
Number of oranges in 60 baskets =62 X 60
= 3720.
6 2
X 6 0
3,7 2 0
Hence, there will be 3720 Oranges.
5) A box of chocolates has 36 slabs in it.How many slabs will there be in 65 boxes?
Number of slabs in 1 chocolate box = 36
Number of slabs in 65 chocolate boxes = 65 X 36
= 2340.
6 5
X 3 6
3 9 0
1, 9 5 0
2, 3 4 0
Hence, there will be 2340 slabs of chocolates box.
9) Raju delivers 257 newspapers each morning. How many newspapers he delivers in 21 days?
Number of newspapers delivered in 1 day = 257
Number of newspapers delivered in 21 days = 257 X 21 = 5397.
2 5 7
X 2 1
2 5 7
5 1 4 0
5,3 9 7
Hence, he delivers 5397 newspapers in 21 days.
16/JUNE/2020
MATHEMATICS
Chapter 6 MULTIPLICATION
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No. 74, 75, Ex. No. 6E, Do No.11 to 18.
Two of them have been done for you.
12) A packet contains 156 books. How many books will 42 packets contain?
Number of books in 1 packet = 156
Number of books in 42 packets = 156 X 42
= 6552.
1 5 6
x 4 2
3 1 2
6 2 4 0
6 5 5 2
Hence, it will contain 6552 books.
15) There are 18 schools in a town. Each school has 400 students in it. How many students are there in the town?
Number of students in 1 school = 400
Number of students in 18 schools = 400 X 18
= 7200.
= 7200.
4 0 0
x 1 8
3 2 0 0
4 0 0 0
7 2 0 0
Hence, there are 7200 students.
17/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Division means equal distribution or Division as repeated subtraction.We shall recapitulate the same and also learn division extensively.
The sign of division is ÷
NOW WATCH THE VIDEO.
Division as equal distribution
Suppose we want to distribute 8 apples. We want to give 2 apples to each child. Our aim is to find how many children would share these eight apples?
8 - 2 = 6
6 - 2 = 4
4 - 2 = 2
2 - 2 = 0
Therefore,8 ÷ 2 = 4We read it as "8 divided by 2 is equal to 4".
Here 8 is called the dividend, 2 is called the divisor and 4 is called the quotient.
Division as repeated subtraction
If we want to divide 20 by 5,
We repeatedly subtract 5 from 20.
20 - 5 = 15
15 - 5 = 10
10 - 5 = 5
5 - 5 = 0
We stop at 0 because we cannot subtract 5 from 0.
Thus when we divide 20 by 5, the answer is 4.
20 ÷ 5 = 4We read it as "20 divided by 5 is 4".
20 is called the dividend, ÷ is the sign of division, 5 is called the divisor, 4 is called the quotient.
Division as inverse of multiplication
We know that 6+6+6+6 = 24 or 4 X 6 = 24.We have also learnt that 24 ÷ 6 = 4 and 24 ÷ 4 = 6
From this we notice that division is the inverse process of multiplication fact.
4 X 7 = 28 gives rise to two division facts:
a) 28 ÷ 7 = 4 b) 28 ÷ 4 = 7.
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No.77, Ex No. 7A, Do No.1 ( a to l ).
Two of them have been done for you.
a) 12 ÷ 4
12 - 4 = 8
8 - 4 = 4
4 - 4 = 0
Therefore, 12 ÷ 4 = 3.
k) 64÷8
64 - 8 = 56
56 - 8 = 48
48 - 8 = 40
40 - 8 = 32
32 - 8 = 24
24 - 8 = 16
16 - 8 = 8
8 - 8 = 0
Therefore, 64 ÷ 8 = 8.
18/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No. 78, Ex No. 7A, Do No. 2 (a to l).
Three of them have been done for you.
a) 25 ÷ 5= 5
Dividend = 25
Divisor = 5
Quotient = 5
f) 24 ÷ 6 = 4
Dividend= 24
Divisor = 6
Quotient = 4
k) 40 ÷ 8 = 5
Dividend = 40
Divisor = 8
Quotient = 5
19/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book Pg No. 78, Ex No. 7A, Do No. 3 ( a to l ).
Three of them have been done for you.
a) 6 X 4 = 24
24 ÷ 4 = 6
24 ÷ 6 = 4.
f) 6 X 6 = 36
In this case, there is only one division fact.
36 ÷ 6 = 6.
j) 3 X 9 = 27
27 ÷ 3 = 9
27 ÷ 9 = 3
20/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No. 78, Ex No. 7A, Do No.4 (a to l).
Three of them have been done for you.
a) 21 ÷ 7 = 3
7 X 3 = 21
3 X 7 = 21
g) 56 ÷ 7 = 8
7 X 8 = 56
8 X 7 = 56
l) 15 ÷ 5 = 3
3 X 5 = 15
5 x 3 = 15.
22/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No. 78, Ex No. 7A, Do No. 5 ( a to l ).
Three of them have been done for you.
a) 36 ÷ 4 = 9 .
g) 64 ÷ 8 = 8.
k) 100 ÷ 5 = 20.
23/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Properties of Division
NOW WATCH THE VIDEO.
Eg - 5 ÷ 1 = 5.
Property 2: If any number except zero is divided by the number itself the quotient is always 1.
Eg - 3 ÷ 3 = 1.
Property 3: The division of any number by 0 has no meaning. We know that division is a repeated subtraction. Let us try to subtract, 0 from 8
Eg - 8 - 0 = 8.
Ex - 0 ÷ 6 = 0.
Property 2: If any number except zero is divided by the number itself the quotient is always 1.
Eg - 3 ÷ 3 = 1.
Property 3: The division of any number by 0 has no meaning. We know that division is a repeated subtraction. Let us try to subtract, 0 from 8
Eg - 8 - 0 = 8.
We cannot divide any number by zero.
Property 4: If we divide 0 by any number except 0 the quotient is always 0.Ex - 0 ÷ 6 = 0.
Hence, we conclude that when 0 is divided by any number (other than zero) the quotient is zero.
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No.79, Ex No. 7B, Do No.1 to 15.
Four of them have been done for you.
1) 0 ÷ 3 = 0
5) 10 ÷ 1 = 10
10) 15 ÷ 15 = 1
14) 9 ÷ 1 = 9
24/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Long Division Method with the help of multiplication table.
NOW WATCH THE VIDEO.
Dividend = Divisor X Quotient + Remainder.
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No. 80, Ex No. 7C, Do No. 1 to 12.
Three of them have been done for you.
1) 12 ÷ 3
3) 1 2 (4
1 2
0 0
Quotient = 4
6) 64 ÷ 8
8 ) 6 4 (8
6 4
0 0
Quotient = 8
11) 30 ÷ 5
5) 3 0 (6
3 0
0 0
Quotient = 6
25/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Division of 2 ,3 and 4 digit by 1 digit without Remainder
NOW WATCH VIDEO 1 FOLLOWED BY VIDEO 2.
VIDEO 2.
Assignment: Complete all exercises in your Mathematics-OCB
26/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Division with Regrouping
Divide 75
Solution:
Step 1: We arrange the given numbers
75 = 7 tens + 5 ones.
We begin with the division of tens.
Step 2: Division of tens: we have 7 tens .
3 goes in 7, two times, so we write 2 in the tens place in the quotient and subtract the product 3 X 2 = 6 tens from 7 tens to get the remainder as 1 ten.
7 tens - 6 tens = 1 ten
Step 3: Division of ones. Now bring down 5 ones and write it to the right of the remainder 1 ten.
1 ten ,+ 5 ones = 10 ones + 5 ones = 15 ones
Now, 3 goes in 15 five times. So, we write 5 in the one's place in the quotient. Subtract
the product 3 X 5 = 15 ones from 15 ones to get the remainder as 0 ones
15 ones - 15 ones = 0 ones.
3) 7 5 (25
6
1 5
3) 7 5 (25
6
1 5
1 5
0
NOW WATCH THE VIDEO.
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No. 85, Ex No. 7E, Do No. 1 to 14.
Three of them have been done for you.
1) 51 ÷ 3
3) 5 1 (17
3
2 1
2 1
0
7) 936 ÷ 4
4) 9 3 6 (234
8
1 3
1 2
1 6
1 6
0
14 ) 920 ÷ 8
8 ) 9 2 0 (115
8
1 2
8
4 0
4 0
0
29/JUNE/2020
MATHEMATICS
Chapter 7 DIVISION
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No.85, Ex No.7E, Do No.15 to 28.
Three of them have been done for you.
Division with Remainder
30/JUNE2020
MATHEMATICS
Chapter 7 DIVISION
Now watch this video:
Explanation:
Divide 79 by 4
4 ) 79 ( 19
4
39
36
03
Hence, Quotient = 19, Remainder = 3.
Verification: We know that
Dividend = Quotient X divisor + Remainder
= 19 x 4 + 3 = 76 + 3 = 79.
Hence, the result is verified.
Assignment: Complete all exercises in your Mathematics-OCB
Mathematics book, Pg No. 88, Ex No.7F, Do No. 1 to 12.
Three of them have been done for you.
1) 68 ÷ 5
5 ) 68 ( 13
5
18
15
03
Hence, Quotient= 13, Remainder = 3
Dividend = Quotient X divisor + Remainder
= 13 X 5 + 3 = 65 + 3 = 68.
6) 97 ÷ 8
8 ) 97 ( 12
8
17
16
01
Hence, Quotient = 12, Remainder = 1
Dividend = Quotient X divisor + Remainder
= 12 X 8 + 1 = 96 + 1 = 97.
11) 842 ÷ 7
7 ) 842 ( 120
7
14
14
02
0
2
Hence, Quotient = 120, Remainder = 2.
Dividend = Quotient X divisor + Remainder
= 120 X 7 + 2= 840 + 2 = 842.
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