2 ARCHIVE MATHEMATICS CLASS 2 (APRIL MAY & JUNE)

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                      28/APRIL/2020                     

MATHEMATICS

NUMBER NAMES
Introduction
Numbers are used every where and especially in Maths. For example - 1, 2, 3, 4, 5....etc. A number is a mathematical tools which is used in counting. 

WATCH THESE VIDEOS TO UNDERSTAND BETTER

    

ASSIGNMENTS

1. What is a number ?

2. Write the number names.

    52 - Fifty two

    132 - One hundred thirty two 

3. Match the following .

    87  - Seventy Five

    93  - Eighty Seven

    75  - Ninety three                                                

4. Write the figure of the following.                                               

i) Seventy seven.               ii) Three.                         iii) Zero.  

iv) Twenty.                        v) Thirty eight.                vi) Nineteen.

vii) Ninety nine.                viii) Sixty one. 

                      29/APRIL/2020                     

MATHEMATICS

Expanded and Compact form of Numbers
Expanded form - When we expand a number to show the value of each digit, we are writing that number in expanded form. Writing numbers in expanded form just means that we are showing the value of each digit in the number. For example - 47 = 40 + 7

HINT

Compact form- Normal form is a way to write very large or very small numbers in a more compact form. For example - 30 + 6 = 36

WATCH THESE VIDEOS TO UNDERSTAND BETTER

    

ASSIGNMENTS                                          

i) Write in expanded form.                             

    a) 47                    b) 98                         c) 45                          d) 62                          e) 33                                                                  

ii)Write in compact form.                                 

    a) 90 + 5 =.            b) 80 + 3 =.                c) 30 + 7 =.                 d)50 + 4 =.                 e) 70 + 2 =.                                                               

                      30/APRIL/2020                     

MATHEMATICS

Before, After and Inbetween Numbers

Before  number - Before number means the predecessor which is 1 less or 1 smaller than the given number. That is if you subtract 1 from the given number, we get the predecessor of that number. 

For example  - The predecessor of 92 is 91 (92 - 1 = 91)                                                  

After number - After number means the successor which is 1 more or 1 greater than the given number. That is if you add 1 to the given number we get the successor of that number.

For example - The successor of 87 is 88 (87 + 1 = 88)                           

In between number 

i) 56      57     58                            ii) 125     126     127                             iii)  219       220       221

ORAL PRACTICE WITH THE HELP OF PARENTS

WATCH THESE VIDEOS TO UNDERSTAND BETTER

  

ASSIGNMENTS                                                
1. Fill in the blanks.                                            
a) The number before 41 is _____.                     b) The number after 58 is _____.                           
c) The number between _____ and 28.               d) The number after 45 is _____.                           
e) The number before is _____ is 47.  

2. Fill in the blanks.
a) 87  ____   89                b)  324  _____   326                c) 750   _____ 751       
d) ____     235                  e)   _____   784                       f)  450     _____.                                    

                      1/MAY/2020                     

MATHEMATICS

Greatest and Smallest Numbers

Ascending Order

Numbers are said to be in ascending order when they are arranged from the smallest to the largest number.E.g. 5, 9, 13, 17 and 21 are arranged in ascending order.

Descending Order

Numbers are said to be in descending order when they are arranged from the largest to the smallest number. E.g. 25, 21, 17, 13 and 9 are arranged in descending order.

To find the greatest or smallest number among the numbers, We would have to arrange the given numbers either in ascending order or descending order. If you are arranging in ascending order then the rightmost number will be greatest number and the leftmost number will be smallest number. If you are arranging in descending order then the leftmost number will be greatest number and rightmost number will be smallest number. For example - Suppose You have to find greatest and smallest number among 253, 452, 616, 325 and 463.

In ascending order - 253, 325, 452, 463, 616. Here, the leftmost number is 253 that's why the smallest number is 253 and the rightmost number is 616 that's why greatest number is 616.

In descending order: 616, 463, 452, 325, 235.  Here, the rightmost number is 235 that's why the smallest number is 253 and the leftmost number is 616 that's why greatest number is 616.

ASSIGNMENTS

1. Tick ( ✓ ) the greatest number and ( × ) the smallest number in each group.               

a) 312.      682.        379.        485.             

b) 132.      128.        699.        235.       

c) 628.      519.        987.        632.       

d) 187.      927.        621.        126.       

e) 162.      782.        312.        789.    

2. Arrange the following numbers in ascending order. 

(a) 216, 825, 916, 325, 496.                                  (b) 425, 333, 487,.825, 716.                             

(b) 382, 928, 286, 135, 405.                                  (c) 849, 840, 896, 825, 986.                           

3.Arrange the following numbers in descending order. 

(a) 487, 968, 629, 405, 720.                                  (b) 234, 360, 426, 747, 505.                            

(c) 215, 316, 480, 680, 209.                                  (d) 712, 628, 782, 639, 750.                              

                      2/MAY/2020                     

MATHEMATICS

Counting Numbers

Counting numbers are the set of numbers that we use to learn how to count. 1, 2, 3, 4, 5, and so on. They are also called natural numbers. The number which is one more than 99 is hundred.                    

NUMBERS ON AN ABACUS

An abacus has rod named as O, T, H from right to left. O stands for ones , T stands for tens and H stands for hundreds. We place beads on more than 9 beads.  

                                                           

The above example is of an abacus. In the above example 6 beads are in H, 4 beads are in T and 3 beads are in O. That means it represents 643(Six hundred forty seven). An abacus will help us to learn about counting numbers beyond 99.                     

WATCH THESE VIDEOS TO UNDERSTAND BETTER

ASSIGNMENTS
1. Write the names of the following numbers.                                                           

a) 342                        b) 590                        c) 432                        d) 168                          e) 962 

2. Represent the following in an Abacus.

a) 503                        b) 431.                       c) 608                        d) 295                          e) 558

                      4/MAY/2020                     

MATHEMATICS

Missing Numbers

Missing numbers are the numbers that are missing in a series of numbers. They have similar differences among them. To find Missing Numbers you will have to look for similar changes between the series of numbers and filling in the missing one. 

Example:	101	102	_?_	104	_?_	106
Working:	Count forward from 101 to 106 to find out the Missing Numbers
Answer:	101	102	103	104	105	106

Copy the chart given below in your OCB exercise book and fill in the Missing Numbers.

FOR BETTER UNDERSTANDING WATCH THIS VIDEO

Video 01

ASSIGNMENT                                                 

1. Write the missing numbers as directed in the blanks. The first one has been done for you.

Question A:	541	543	_?_	547	_?_	551	_?_	555	_?_	559
Working:	Count in twos to find out the Missing Numbers
Answer:	541	543	545	547	549	551	553	555	557	559

Question B:	875	_?_	_?_	890	_?_	900	_?_	910	915	920
Working:	Count in fives to find out the Missing Numbers
Answer:	875	___	___	890	___	900	___	910	915	920

Question C:	211	212	_?_	214	_?_	216	217	_?_	219	220
Working:	Count forward from 211 to 219 to find out the Missing Numbers
Answer:	211	212	___	214	___	216	217	___	219	220

Question D:	440	_?_	_?_	437	_?_	435	_?_	_?_	432	431
Working:	Count in reverse (backwards) to find out the Missing Numbers
Answer:	440	___	___	437	___	435	___	___	432	431

Question E:	770	_?_	_?_	800	810	_?_	830	_?_	850	860
Working:	Count in tens to find out the Missing Numbers
Answer:	770	___	___	800	810	___	830	___	850	860

                      5/MAY/2020                     

MATHEMATICS

Comparing Numbers
To compare two numbers means to find whether;-                                                             

1) One number is greater than another number. (>)
2) One number is less than another number. (<)
3) One number is equal to another number. (=)
If the number on the left is greater than the number on the right, we put the (greater than) '>' sign.       

If the number on the left is smaller than the number on the right, we put the (less than) '<' sign.       

If both the numbers are same, we then put the (equal to) '=' sign.

EXAMPLE : Compare 839 and 97.                                      

Here, 839 has 3 digits and 97 has 2 digits.                                                

So, 839 > 97.   

EXAMPLE : Compare 546 and 731.                                    

Compare 5 and 7 ; 5 < 7.                         
So, 546 < 731. 

Now watch this video....      

ASSIGNMENT                                                  

1. Put the correct sign > ( greater than), < ( less than) and = ( equal to).                          

(a) 100___121.                 (b) 555___558.              (c) 580___579.               (d) 980___980.              

(e) 900___900.                 (f) 763___760.               (g) 236___49.                 (h) 809___809.              

(i) 459___464.                  (j) 674____690.

                     6/MAY/2020                     

MATHEMATICS

Place Value

The place value of a digit in a number depends upon its place or position. In Maths, every digit in a number has a place value.   

EXAMPLE 1.Write the place value of all the digits in 374.

H	T	O
3	7	4

There are 3 hundreds in the above number. So, the place value of the digit 3 is 3 × 100 = 300.

There are 7 tens in the above number. So, the place value of the digit 7 is 7 × 10 = 70.

There are 4 ones in the above number. So, the place value of the digit 4 is 4 × 1 = 4.

EXAMPLE : 2. See the place value of the digit 4 in a), b) and c) below.
a) 452         4 hundreds  = 4 × 100 = 400.
b) 347         4 tens.         = 4 × 10 = 40.
c) 234         4 ones.        = 4 × 1 = 4.
REMEMBER: The place value of zero is always zero.    

Now watch this video...  

                                                     

ASSIGNMENT  

Write the place value of the circled digit in each of the following.  

                     7/MAY/2020                     

MATHEMATICS

Face Value

The face value of a digit in a number is equal to the digit itself. The face value does not depend upon the place or position of a digit in the number.

                

EXAMPLE 1 : Consider the numbers 698 and 263.             

The face value of 6 hundreds in 698 is 6 and the face value of 6 tens in 263 is also 6.  

EXAMPLE 2 : Write the face value and place value of all the digits in the number 574.                             Digit.                          Face Value.                            Place Value.             
         5                                     5                                       5 × 100 = 500.           
         7                                     7                                       7 × 10 = 70.             
         4                                     4                                       4 × 1 = 4        

Now watch this video...

ASSIGNMENT                                             

1.Write the face value of the circled digits in the following cases. 

2 . Fill in the blanks.                                    

(a)  In 735, the place value of 7 is ____ and the face value of 7 is ____.      

(b)  In 582, the place value of 8 is ____ and the face value of 8 is  ____.    

(c)  In 678, the place value of 7 is  ____ and the face value of 7 is ____.    

(d)  In 456, the place value of 5 is  ____ and the face value of 5 is ____.    

(e)  In 749, the place value of 9 is  ____ and the face value of 9 is ____.

                     8/MAY/2020                     

MATHEMATICS

Compact Form
To write an expanded number in compact form we arrange the number under hundreds, tens, and ones columns and write the extreme left digits each term.        

EXAMPLE 1 : Write the standard form of  900 + 8.                
9 hundreds   +   0 tens   +   8 ones  =   900  +   00    +    8    =     908      

EXAMPLE 2 : Write the standard form of 600 + 90.              
6 hundreds   +   9 tens   +   0 ones   =   600  +   90    +         =     690  


FOR BETTER UNDERSTANDING WATCH THE VIDEO     

                                                 

ASSIGNMENT   

1. Write the numbers in the compact form.                                                   
(a) 400 + 50 + 7 =                                           
(b) 600 + 7         =                                           
(c) 100 + 20 + 4 =                                           
(d) 800 + 90 + 5 =                                         
(e) 700 + 40        =                                         

2. Write the following in the standard form.                                                  
(a) 8 hundreds + 7 tens + 3 ones =  873      
(b) 7 hundreds + 8 tens + 9 ones =                
(c) 2 hundreds + 5 tens + 7 ones =              
(d) 4 hundreds + 6 tens + 3 ones =              
(e) 5 hundreds + 0 tens + 6 ones =    

                     9/MAY/2020                     

MATHEMATICS

Expanded Form
We have already learnt about the expanded form of two-digit numbers. Let us now learn about three digits numbers and their expanded form.

100 is the smallest three-digit number

999 is the greatest three-digit number

Now watch this video....EXAMPLE 1
Consider the number 742.
We know that 742 = 7 hundreds + 4 tens + 2 ones.
Writing the place values of the digits, we get, 
7 Hundreds = 700 
4 Tens.        = 40
2 Ones.       = 2 
Thus, the expanded form of 742 is as shown below.
742 = 700 + 40 + 2. 

EXPANDED FORM OF A THREE DIGIT NUMBER CONTAINING ZERO
EXAMPLE 2
Consider the number 302. 
302 = 3 hundreds + 0 tens + 2 ones.
Writing the place value of the digits, we get, 
3 hundred = 300.
0 tens.    = 0.
2 ones.   = 2.  
Thus, the expanded form of 302 is as shown below.
302 = 300 + 0 + 2 or 302 = 300 + 2. 

ASSIGNMENT  
Write the expanded forms of the following in your OBC exercise books.
(a) 204 = 200 + 0 + 4. 
(b) 310 = 
(c) 452 =
(d) 682 =
(e) 925 =
(f) 516 = 
(g) 144 =
(h) 509 =

                     11/MAY/2020                     

MATHEMATICS

Addition

Addition is when you add two numbers or more and make a bigger number. The sign of addition is '+' ( plus ). The answer we get after adding is called the sum. 

                                                           

PROPERTIES OF ADDITION                       

1. The sum obtained upon addition of 2 or more numbers remains the same even after changing their order.                              
EXAMPLE :   22 + 33 = 55         OR      33 + 22 = 55                                

2. The sum obtained after adding 0 to any number is the number itself.                          
EXAMPLE :  i)  48 + 0 = 48                      ii) 56 + 0 = 56                                 

3. The sum obtained after adding 1 to any number is the next number, also called the successor of that number.                       
EXAMPLE :   i) 57 + 1 = 58                      ii) 75 + 1 = 76          

ASSIGNMENT                                                
1. By actual calculation, prove that the sum of the following remains same after reversing the order.      
 (a) 32 + 45                 (b) 95 + 21                    (c) 125 + 3                     (d) 29 + 39                                 
2. Add the following.                             
   (a) 83 + 0                     (b) 94 + 0                     (c) 21 + 0                       (d) 45 + 0                                  
3. Find the successors of the following.                                                 
   (a) 25                            (b) 39                            (c) 123                           (d) 145.     

                   12/MAY/2020                     

MATHEMATICS

Addition of two Digit Numbers using column method

To add two digit numbers using column method, First arrange the numbers vertically so that the tens' place digits and ones' place digits are lined up which means in simple one number should be written above the other number. Draw a line under the bottom number.

For example: Addition of 57 and 16.

Now watch this video.... 

ASSIGNMENT  

i) Do the given questions in OCB Notebook.

  

                   13/MAY/2020                     

MATHEMATICS

Adding using regrouping Ones into Tens and Ones          
In addition, if the sum at the ones place is ten or more, we regroup the ones in such a way that ten ones are carried to the tens place as one ten and we write the remaining ones at the ones place. 
For example: 13 ones = 10 ones + 3 ones.                         
On regrouping the ones , we can write it as, 1 ten + 3 ones = 13                               

EXAMPLE : Regroup 4 tens and 11 ones                       
4 tens and 11 ones 
= 4 tens + 10 ones + 1 one.                             
= 4 tens + 1 ten + 1 one.                
= 5 tens + 1 one = 51     
             
Now watch this video.... 

                                                       

ASSIGNMENT
1. Do the given sums in OCB Notebook.
i) 2 tens 5 ones + 5 tens 3 ones
ii) 12 tens 8 ones + 8 tens  7 ones
iii) 15 tens 4 ones + 12 tens 6 ones
iv) 9 tens 13 ones + 7 tens 2 ones
v) 25 tens 9 ones + 23 tens 8 ones

                   14/MAY/2020                     

MATHEMATICS

Addition of two digit numbers(carry over)

You have been already explained in the previous classes how to add two digit numbers. Here, we are going learn how to add two digit three numbers using column method.

EXAMPLE  : Add 67 , 21 and 13.                   
METHOD: First, we will arrange the numbers in column.
                   1 
               Tens      Ones
                   6           7
                   2           1
                   1           3       
                 10           1
   
Step 1 : Add the ones together.                             
             7 ones + 1 ones + 3 ones = 11 ones   =   10 ones + 1 one = 1 ten + 1 one                                                 Write 1 under ones column and carry over 1 ten to the tens column.                                 

Step 2 : Add the tens together including the carry over. 
              6 tens + 2 tens + 1 ten + 1 ten ( carry over ) = 10 tens 

ASSIGNMENT

1. Find the sum.

                   15/MAY/2020                     

MATHEMATICS

Addition of three digit numbers.

You have been already explained in the previous classes how to add two digit numbers. Here, we are going to learn how to add three digit numbers using column method.

EXAMPLE  : Add 231 , 342 and 425.                   
METHOD: First, we will arrange the numbers in column.
                    
         Hundreds     Tens      Ones
                   2             3             1
                   3             4             2
                   4             2             5      
                   9             9             8.

   Step 1 : Add the ones together.                             
             1 one + 2 ones + 5 ones = 8 ones                                  

Step 2 : Add the tens together. 
              3 tens + 4 tens  + 2 tens    =   9 tens 

Step 3 : Add hundreds digits together.
              2 hundreds   +   3 hundreds   +  4 hundreds   =   9 hundreds        

ASSIGNMENT

1. Find the sum.

                   16/MAY/2020                     

MATHEMATICS

Addition

We have already learnt about the addition of two and three digits. Now, we will practice these.

1. Do the given sums. 

                 18/MAY/2020                   

MATHEMATICS

Word Problem on Addition
Read the problem carefully. Study what is given and what is asked for. Write the steps clearly and then solve the problem.
EXAMPLE 1 : A shopkeeper sold 221 books on the first day, 195 books on the second day and 129 books on the third day. How many books did he sell altogether?
SOLUTION : What is given in the problem? Number of books sold by a shopkeeper. What are we asked to find out? Total number of books the shopkeeper sold on three days. How can we find this
out ? By addition.       
Books sold on the first day =     221.
Books sold on the second day = 195.
Books sold on the third day =     129.
Total number of books sold =      545.
Altogether 545 books were sold.

ASSIGNMENT.
Q.no. 1. There are 27 girls and 35 boys in a class. How many students are there in the class?
Q.no. 2. Amita got 75 marks in Hindi written exam and 19 marks in Hindi oral exam. Find the total marks in Hindi ?
Q.no. 3. There were 350 people in one train and 756 people in another. How many people were there in both trains?
Q.no 4. In a factory, 256 male and 412 female workers are working. Find the total number of workers in the factory. 

     19/MAY/2020     

MATHEMATICS

Read the problems carefully maybe even a second time to understand it clearly.
First, study what is given and what is asked for. Then, write the steps clearly before you solve the problem.

Question: 40 men, 48 women and 23 children live in a building. How many people live there altogether ?

Number of men	=	40
Number of women	=	48
Number of children	=	23
Hence, the total number of people living in the building
	=	No. of men	+	No. of women	+	No. of children
	=	40	+	48	+	23
	=	111

Therefore, 111 people live in the building.                      

ASSIGNMENT. 
Solve the following problems in your OCB-mathematics notebook.

1)      At a meeting there were 569 men and 356 women. How many people were at the meeting?    

2)      In a stationary shop, there are 184 black pens, 232 red pens and 325 blue pens. How many pens are there in the shop?                                                                 

3)      In a cricket match, a team scored 256 runs in the first inning and 379 in the second inning. How many runs in all were scored by the team?                                       

4)      There are 288 apples in one basket and 174 apples in another basket. How many apples are there in both baskets?

     20/MAY/2020     

MATHEMATICS

Self Assessment Test 

Answer the following questions in your OCB-Mathematics notebook. 

1. Write in words.

i) 234              ii) 507            iii) 444            iv) 978           v) 312

2. Write in Numerals.

i)   Seven hundred seventy seven

ii)  One thousand three hundred forty

iii) Five hundred sixty five.

iv) Eight hundred five

v)  One hundred eighty seven   

3. Fill in the blanks.

i)   The number before 41 is ________.

ii)  The number after 58 is ________.

iii) The number before _______ is 47.

iv) The number after _______ is 16.

v)  27 is in between _______ and 28.

4. Arrange the following numbers in descending order (big to small). One has been done for you.

i) 382, 928, 286, 135, 405 

Ans: 928, 405, 382, 286, 135

ii) 849, 840, 896, 825, 986.

iii) 487, 968, 629, 405, 720

iv) 215, 316, 480, 680, 209

v) 712, 628, 782, 639, 750

     21/MAY/2020     

MATHEMATICS

Self Assessment Test 

Answer the following questions in your OCB-Mathematics notebook.

1. Put the correct sign >(greater than), <(less than) or =(equal to).

a) 580 _____ 579

b) 763 _____ 760

c) 674 _____ 690

d) 236 _____ 236

e) 575 _____ 557

2. Write the place value of the highlighted digits. One has been done for you.

a) 2 7 8 =  7 tens    =  7 x 10 = 70

b) 3 4 7 

c) 8 7 1

d) 9 0 4

e) 2 1 6

3. Write the expanded forms of the following. One has been done for you.

a) 452 = 400 + 50 + 2

b) 516 = 

c) 509 =

d) 144 =

e) 682 = 

f)  310 =

4. Write the numbers in the compact form. One has been done for you.

a) 400 + 50 + 7 = 457

b) 600 + 7 =

c) 700 + 40 =

d) 200 + 20 + 8 =

e) 8 hundreds + 7 tens + 3 ones =

f) 2 hundreds + 5 tens + 7 ones =

     22/MAY/2020     

 MATHEMATICS

Self Assessment Test 

Do the given sums in your OCB-Mathematics exercise-book. One example has been given for you to understand better.

     23/MAY/2020     

 MATHEMATICS

Self Assessment Test 

Solve the following problems in your OCB-Mathematics exercise-book.

Example
First, study what is given and what is asked for. Then, write the steps clearly before you solve the problem.
Question: 40 men, 48 women and 23 children live in a building. How many people live there altogether ?

Number of men	=	40
Number of women	=	48
Number of children	=	23
Hence, the total number of people living in the building
	=	No. of men	+	No. of women	+	No. of children
	=	40	+	48	+	23
	=	111

Therefore, 111 people live in the building.

With the help of the example, solve the following problems.

1)      Nancy has 123 green marbles, Tom has 78 red marbles and Sam has 125 blue marbles. How many marbles do they have altogether?

2)      In a library, there are 281 books in Hindi, 454 books in English and 279 books in Science. How many books are there in the library?

3)      Lucy went to the grocery store. She bought 12 packs of cookies and 16 packs of noodles. How many packs of groceries did she buy in all?

4)      In a school, there are 542 girls and 387 boys. How many pupils are there in that school?

5)      Alice collects 359 coins. Alice's father gives Alice 78 more. How many coins does Alice have?   

     26/MAY/2020     

 MATHEMATICS

SUBTRACTION

Taking away a number from another number is called Subtraction. When we subtract, the number of things in the group reduce or become less. Subtraction is signified by the minus sign (—).            

PROPERTIES OF SUBTRACTION                  

PROPERTY 1 : The difference of a number and zero (0) is always the number itself.             

7 - 0 = 7.                  5 - 0 = 5.                     

PROPERTY 2 : The difference of a number from itself is always zero (0).                              

6 - 6 = 0.                   8 - 8 = 0.                     

PROPERTY 3 : If we subtract 1 from a number, we get the previous number.                

5 - 1 = 4.                   9 - 1 = 8.                     

Now watch the video.........

ASSIGNMENT                                                  

1. Fill in the blanks. 

1	12 – 0 =			6	10 – 0 =
2	25 – 25 =			7	5 – 1 =
3	13 – 0 =			8	3 – 1 =
4	12 – 12 =			9	9 – 0 =
5	17 – 17 =			10	6 – 1 =

                                             

     27/MAY/2020     

 MATHEMATICS

Subtraction is the term used to describe how we 'take away' one or more numbers from another. Subtraction is also used to find the difference between two numbers.ASSIGNMENT

Solve the following subtractions in your OCB-Mathematics exercise-book.

1	10 - 3 =			6	23 - 5 =
2	17 - 8 =			7	9 - 2 =
3	20 - 5 =			8	13 - 7 =
4	18 - 6 =			9	11 - 4 =
5	36 - 8 =			10	29 - 6 =

     28/MAY/2020     

 MATHEMATICS

Subtraction of two digit number without carry 

For subtracting 2 - digit numbers we will subtract or minus a two digit number from another two digit number. To find the difference between the two number we need to subtract 'ones from ones' and 'tens from tens'.                                                                  

EXAMPLE : Subtract 35 from 58.                                      

Step 1: First arrange the numbers vertically so that the tens' place digits and ones' place digits are lined up which means in simple one number should be written above the other number.                                                

                       5     8

                    -  3     5     

                                                             

Step 2 : Subtract the digits in the ones place. Subtract (8 - 5 = 3). Place 3 in the ones column as shown.                                            

                        5     8

                      - 3     5     

                               3  

                                                                     

Step 3 : Subtract the digits in the tens place. Subtract ( 5 - 3 = 2). Place 2 in the tens column as shown.

                        5     8

                      - 3     5     

                        2     3

Step 4 : The difference of 58 - 35 is 23. 

ASSIGNMENT
Do the following subtraction in OCB notebook.

     29/MAY/2020     

 MATHEMATICS

Subtraction with carry over

Sometimes, when you are subtracting large numbers, the top digit in a column is smaller than the bottom digit in that column. In that case, you need to borrow from the next column to the left. Borrowing is a two-step process:

Step 1: Subtract 1 from the top number in the column directly to the left.

             Cross out the number you’re borrowing from, subtract 1, and write the                         answer above the number you crossed out.

Step 2: Add 10 to the top number in the column you were working in.

            

For example, suppose you want to subtract 386 – 94. 

First arrange the given numbers as follows and subtract 4 from 6 in the ones column, which gives you 2:

                                  3   8   6

                               -       9   4   

                                            2

When you move to the tens column, however, you find that you need to 
subtract 8 – 9. Because 8 is smaller than 9, you need to borrow from the hundreds column. First, cross out the 3 and replace it with a 2, because 3 – 1 = 2:

                                  2

                                  3   8   6

                               -       9   4   

                                            2

Now, 8 will become 18, because 8 + 10 = 18. Cross 8 and write 18 above it.

                                  2   18

                                  3    8    6

                               -        9    4   

                                              2

Now you can subtract in the tens column: 18 – 9 = 9

                                  2   18

                                  3    8    6

                               -        9    4   

                                        9    2

The final step is simple: 2 – 0 = 2

                                  2   18

                                  3    8    6

                               -        9    4   

                                  2    9    2

Therefore, 386 – 94 = 292.

Now watch the video......

Assignment

Do the given subtractions in OCB notebook.

     30/MAY/2020     

 MATHEMATICS

               Self Assessment Test on subtraction

Do the given subtractions in your OCB notebook.

a) 10 - 3 =			b) 13 - 0 =			c) 27 - 8 =
d) 17 - 6 =			e) 37 - 9 =			f) 18 - 5 =

g) In your Mathematics-OCB draw and colour the turtle according to the colour scheme given below by first solving the subtraction exercise within each portion of the drawing. Only after getting the correct answers will you be able to colour the turtle correctly. "HAVE FUN WITH Mr. TURTLE"

     01/JUNE/2020     

 MATHEMATICS

Do the following subtractions in your Mathematics-OCB.

	T	O			T	O			T	O			T	O
	5	0			5	3			4	6			4	5
-	4	0		-	2	3		-	2	1		-	1	2
	T	O			T	O			T	O			T	O
	8	3			3	6			4	8			4	5
-	7	0		-	1	5		-	2	2		-	1	2
	T	O			T	O			T	O			T	O
	9	6			5	7			6	6			9	3
-	6	0		-	3	6		-	2	2		-	5	1

     02/JUNE/2020     

 MATHEMATICS

Do the following subtractions in your Mathematics-OCB.

	H	T	O			H	T	O			H	T	O			H	T	O
	7	8	4			7	1	2			8	9	9			9	9	9
-			2		-		1	1		-			7		-		8	1
	H	T	O			H	T	O			H	T	O			H	T	O
	5	1	8			6	8	9			1	8	4			8	2	6
-			7		-		5	4		-		3	0		-			4
	H	T	O			H	T	O			H	T	O			H	T	O
	9	8	9			2	3	9			4	7	5			5	7	6
-		7	2		-		2	8		-		7	5		-		6	5

     03/JUNE/2020     

 MATHEMATICS

Do the following subtractions in your Mathematics-OCB.

	H	T	O			H	T	O			H	T	O			H	T	O
	2	9	3			7	7	3			3	8	4			7	3	4
-	1	5	1		-	4	7	2		-	1	5	3		-	7	2	0
	H	T	O			H	T	O			H	T	O			H	T	O
	8	3	3			4	4	8			3	6	3			9	9	0
-	7	3	3		-	1	2	5		-	2	4	1		-	7	5	0
	H	T	O			H	T	O			H	T	O			H	T	O
	6	0	9			9	9	9			9	8	6			5	3	6
-	4	0	3		-	5	6	7		-	8	3	6		-	2	1	5

     04/JUNE/2020     

 MATHEMATICS

Do the following subtractions in your Mathematics-OCB.

	H	T	O			H	T	O			H	T	O			H	T	O
	7	3	5			8	6	7			6	6	4			7	2	3
-	2	6	7		-	5	7	8		-	2	9	7		-	3	8	7
	H	T	O			H	T	O			H	T	O			H	T	O
	4	1	3			7	0	3			6	1	5			6	2	5
-	2	4	5		-	3	2	8		-	2	3	6		-	2	8	9
	H	T	O			H	T	O			H	T	O			H	T	O
	4	3	2			6	3	1			5	7	1			6	3	0
-	1	8	4		-	1	2	8		-	1	8	2		-	5	7	9

     05/JUNE/2020     

 MATHEMATICS

Assignment: Do the following exercise in your Mathematics-OCB.
Subtraction

	H	T	O			H	T	O			H	T	O			H	T	O
	2	0	3			9	0	0			7	4	0			5	0	0
-	1	6	5		-			7		-		7	9		-	1	9	0
	H	T	O			H	T	O			H	T	O			H	T	O
	4	0	0			6	0	4			6	1	5			6	2	5
-	2	0	3		-	1	3	1		-	1	7	6		-	5	8	8
	H	T	O			H	T	O			H	T	O			H	T	O
	8	3	2			7	8	5			6	3	0			7	0	0
-	1	9	8		-	2	9	7		-		8	7		-	3	6	9

     06/JUNE/2020     

 MATHEMATICS

Assignment: Do the following exercise in your Mathematics-OCB.
Fill in the blank boxes with the correct number as shown in the example.
Example

	T	O
	8	7	→	7	because	7	-	4	=	3
-	3	4	→	3	because	8	-	3	=	5
	5	3

Exercise

	T	O			T	O			T	O			T	O
	3					5				9				8
-		4		-	1			-	2			-	2
	2	2			3	2			1	3			5	3
	T	O			T	O			T	O			T	O
	6					6			9					6
-		4		-	1			-		7		-	5
	5	5			4	4			7	1			3	1

     08/JUNE/2020     

 MATHEMATICS

Chapter - 4

Solve the following problems in your Mathematics-OCB.

First, study what is given and what is asked for. Then, write the steps clearly before you solve the problem. 
Now watch the video......

Example: A group of soldiers had 65 bags of food. If they used 34, how many bags were left ? 

Solution:

Number of bags soldiers had             = 65

Number of bags used                          = 34

Number of bags left after using          = 65 - 34

                                                               = 31        

Therefore, there are 31 bags of food left.

Assignments:

1. Manan sold 156 mobile phones and Subham sold 133. Who sold more mobile phones and how many more?

2. There are 938 children in a school, 425 are girls. How many boys are there in the school ?

3. A cinema hall had 954 seats. At the matinee show there were only 623 audience. How many seats were vacant ? 

4. 638 people were going to Bengaluru by a train. If 235 people got off at Indore, how many people were left in the train ?

5. A balloon- seller had 448 balloons. He sold 226 balloons. How many balloons were left with him ?

     09/JUNE/2020     

 MATHEMATICS

Chapter - 4 Word Problems

Assignment: Do the following in your Mathematics-OCB.

 of which no. 7 has been done for you.

First, study what is given and what is asked for. Then, write the steps clearly before you solve the problem. 

7. There are 447 seats in an aeroplane. 298 people are travelling in the aeroplane. How many seats are vacant if one seat has only one person sitting in it? 

Total number of seats in the aeroplane	=	447
Number of people travelling	=	298
Number of seats vacant	=	?
Number of seats vacant in the aeroplane	=	Number of seats in the aeroplane	-	Number of people travelling
	=	447	-	298
	=	149
Therefore, there are 149 seats vacant in the aeroplane.

8. There are 500 seats in an auditorium. If 374 people attended a concert held in the auditorium, how many seats were empty ?

9. A shopkeeper bought 76 tins of cheese. He sold 49 tins. How many tins of cheese were left ?

10. 565 children of a school had ice- creams. 218 students had vanilla ice- cream. The rest had chocolate ice- creams. How many children had chocolate ice-creams ?

11. A school took 364 students to Science city. If 167 students were boys, how many students were girls ?

12. The students of classes 2 'A' and 2 'B' made 283 charts in an exhibition. If the 2 'A' students made 139 charts, how many charts did the 2 'B' students make ?

     10/JUNE/2020     

 MATHEMATICS

Chapter - 6 (Multiplication)

Learn the given tables.

Page no. 55

Now watch the video .....

Page no. 58

Now watch the video .....

Assignment: Do the following in you Mathematics-OCB.

Write and memorize the tables of 2 and 4.

     11/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

Study the tables of 2 and 4.

Now watch the video .....

Now watch the video.......

 
Assignment:  

1. Memorize the tables of 2 and 4.
2. Do the following multiplication in your Mathematics-OCB.
a) 2 x 3 = _____

b) 4 x 5 = _____

c) 4 x ___ = 24

d) 2 x 7 = _____

e) ____ x 6 = 12

f) _____ x 8 = 32

g) 4 x 9 = _____

h) 2 x 10 = _____

  12/JUNE/2020  

 MATHEMATICS

Chapter - 6 (Multiplication)

Learn the given tables.

Page no. 58

Now watch the video .....

Page no. 60

Now watch the video .....

Assignment: Do the following in you Mathematics-OCB.
Write and memorize the tables of 3 and 6.

     13/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

Learn the given tables.
Page no. 59

  NOW WATCH THE VIDEO.

Assignment: Do the following in your Mathematics-OCB.
1. Memorize table 7 and revise the tables of 2, 3, 4 and 6 (page no. 58 and 59).

     15/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

Learn the given tables.

Page no. 59

                                                    NOW WATCH THE VIDEO

Page no. 60

Assignment: Do the following in your Mathematics-OCB.

Write and memorize the tables of 5 and 10.

    16/JUNE/2020     

 MATHEMATICS

Chapter - 6 (Multiplication)

Learn the given tables
Page no. 60

                                                 NOW WATCH THE VIDEO.

Page no. 60

                                                   NOW WATCH THE VIDEO.

Assignment: Do the following in you Mathematics-OCB.

1. Memorize the tables of 8 and 9.

2. Do the following multiplication in your Mathematics-OCB.

a) 6 x 3 = _____

b) 8 x 5 = _____

c) 6 x ___ = 24

d) 8 x ___ = 24

e) ____ x 8 = 64

f) ____ x 5  = 40

g) 6 x 9 = _____

h) 8 x 10 = _____

i) 6 x 7 = _____

j) ____ x 4 = 32

     19/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

Revise the tables of 2 to 10 and do the following in your Mathematics -OCB.

(Page no. 60)

(a)		3 × 2 =				(f)		8 × 4 =
(b)		2 × 4 =				(g)		5 × 8 =
(c)		6 × 9 =				(h)		6 × 5 =
(d)		8 × 2 =				(i)		7 × 7 =
(e)		4 × 7 =				(j)		9 × 7 =

     20/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

(Page no. 61)

PROPERTIES OF MULTIPLICATION

PROPERTY 1 : The product of 2 numbers remains the same even after changing the order of the numbers. For example-

5 × 9 = 45        Or       9 × 5 = 45

PROPERTY 2: When a number is multiplied by 1, the product is the number itself. For example-

i) 4 × 1 = 4,                ii) 11 × 1 = 11

PROPERTY 3: When a number is multiplied by 0, the product is always 0.

i) 3 × 0 = 0                 ii) 12 × 0 = 0

Assignment:
Do the following exercises in Mathematics - OCB.

1. Calculate and prove that the product of the following remain the same even after reversing the order.

(a) 7 × 9; 9 × 7

     7 × 9 = 63      Or          9 × 7 = 63

(b) 9 × 5;     5 × 9

(c) 4 × 3;     3 × 4

(d) 5 × 4;     4 × 5

(e) 3 × 7;     7 × 3

(f) 2 × 6;      6 × 2

2. Multiply the following by 1:

(a) 9 × 1 = 9

(b) 8

(c) 6

(d) 4

3 Find the product of the following:

(a) 16 × 0   = 0

(b) 8   × 0   = 

(c) 6   × 0   =

(d) 2   × 0   =

(e) 10 × 0   =

     22/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

Multiplying using a Number Line

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Assignment

Do the the following multiplication (Page no. 62).

3. Multiplication of 2 by 6 using number line.2 + 2 + 2 + 2 + 2 + 2 = ______

                6   x   2     = ______

4. Multiply the following using a number line.
(a) 5 by 3

(b) 2 by 8

(c) 4 by 5

     23/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

5. Recollect the tables and match the following. (pg.no. 63)

(a)	5 x 4			(i) 27
(b)	6 x 8			(ii) 40
©	9 x 3			(iii) 48
(d)	5 x 8			(iv) 18
(e)	7 x 3			(v) 20
(f)	2 x 9			(vi) 21
(g)	5 x 4			(vii) 27
(h)	6 x 8			(viii) 40
(i)	9 x 3			(ix) 48
(j)	5 x 8			(x) 18
(k)	7 x 3			(xi) 20
(l)	2 x 9			(xii) 21

     24/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

6. Count in threes and fill in the boxes. (Pg no. 63)

     25/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

MULTIPLICATION OF TWO-DIGIT NUMBERS BY A ONE-DIGIT NUMBER (WITHOUT CARRYING OVER ON PAGE NO.64/65)

To understand the Multiplication of a two-digit number or a one-digit number, see the following examples. 

EXAMPLES : Multiply 43 by 2.

Method:

Step 1: First multiply the digit 3 which is in the ones place by 2 and write the product below the ones column.

So, 2 × 3 = 6

Step 2 : Then multiply the digit 4 which is in the tens place by 2 and write the product below the tens column.
2 × 4 = 8
Therefore, 43 x 2 = 86

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Assignment

Find the product of the following in Mathematics-OCB (Page no. 64 and 65).

	T	O			T	O			T	O			T	O
	2	4			3	2			1	4			3	2
x		2		x		3		x		2		x		2
	T	O			T	O			T	O			T	O
	1	1			2	4			4	2			4	4
x		7		x		3		x		2		x		2

     26/JUNE/2020     

 MATHEMATICS

Chapter - 6(Multiplication)

MULTIPLICATION OF TWO-DIGIT NUMBERS BY A ONE-DIGIT NUMBER (WITHOUT CARRY OVER ON PAGE NO.64/65)

To understand the Multiplication of a two-digit number a one-digit number, see the following example.

Assignment
Find the product of the following in Mathematics-OCB (Page no.65).

     29/JUNE/2020     

 MATHEMATICS

Chapter - 8(GEOMETRY)

Flat surface: A flat surface which extends in all directions is called a plane. 

Two dimensional: Figures that lie completely in a plane are said to be two dimensional or 2-D figures because they only have length and width. e.g., square, rectangle, triangle, circle, etc.

Properties of 2-D

i)   2-D shapes have only a flat face or surface and have area. 

ii)  They have both sides and vertices except for a circle. 

iii) Face of the 2-D figure is its surface that we can see. 

iv) Its vertex is the point at which its two sides meet.

Some important 2-D shapes

i) Triangle

It has 3 equal or unequal sides and 3 vertices.

ii) Square:

It has 4 sides and 4 vertices. All its sides are equal. It has 2 equal diagonals.

iii) Rectangle:

It has 4 sides (2 long and 2 short) and 4 vertices. It's opposite sides are equal. It has 2 equal diagonals. 

iv) Circle:

It has neither sides nor vertices. It is round in shape.

NOW WATCH THE VIDEO.

 Assignment:

Learn about 2-D shapes (page no. 76)

     30/JUNE/2020     

 MATHEMATICS

Chapter - 8(GEOMETRY)

SOME MORE 2-D SHAPES

Oval : It has neither sides nor vertices. It is more elongated than a circle.

Hexagon : It has 6 sides which may or may not be equal. It has 6 vertices.

Rhombus : It has 4 equal sides and 4 vertices. It has 2 unequal diagonals.

 

Assignment:

Learn about 2 D shapes.