CLASS 3 ARCHIVE MATHEMATICS (MAY TO SEPTEMBER)

 

15/SEPTEMBER/2021

CHAPTER 6 MULTIPLICATION

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MULTIPLYING BY MULTIPLES OF 10 i.e., 20, 30, 300 etc.

Assignment:- Do Ex- 6B, page No.69, No. 27 to 52 in your Mathematics-OCB.

13/SEPTEMBER/2021

CHAPTER 6 MULTIPLICATION

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MULTIPLYING BY 10,100,1000

Assignment:- Do Ex- 6B, page No.69, No. 1 to 26 in your Mathematics-OCB.

08/SEPTEMBER/2021

CHAPTER 6 MULTIPLICATION

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LET US REVISE

We know that multiplication is repeated addition. To find the sum equal amounts are added repeatedly, we can multiply to find the same result in a much easier and quicker way.

Below are given four groups of flowers with 5 flowers in each group.

How many flowers are there altogether ? We can add 5 + 5 + 5 + 5 = 20

20 flowers in all

MULTIPLICATION TABLES
We have learnt the multiplication tables upto 10 in the previous class. Below we show how multiplication table of 2 can be built up. In the similar way, tables of other numbers can be built up.

MULTIPLICATION GRID

Suppose we want to find the product of 2 numbers with the help of a multiplication grid.

The numbers along the top and side are factors.
Suppose we have to find 3 × 5

MULTIPLES
We can obtain the multiples of any counting number by multiplying this counting number by the counting numbers 1, 2, 3, 4, 5, ... .

Thus, multiples of 2 are 2 × 1, 2 × 2, 2 × 3, 2 × 4, 2 × 5 that is 2, 4, 6, 8, 10, ... .

PROPERTIES OF MULTIPLICATION

MULTIPLICATION BY A ONE-DIGIT NUMBER

Assignment:- Do Ex- 6A, page No. 66, No. 1 to 20 in the text book and No. 21 to 24 in your Mathematics-OCB.

06/SEPTEMBER/2021

CHAPTER 5 MULTIPLICATION TABLES UPTO 10 X 20.

Assignment:- Learn tables 11 to 20  

Do Ex- 5A, page No. 60, No. 3 to 16 in your Mathematics-OCB.

01/SEPTEMBER/2021

CHAPTER 5 MULTIPLICATION TABLES UPTO 10 X 20 

In previous class, we have learnt multiplication tables Upto  10 x10 . The multiplication tables are very useful in the multiplication and division of numbers. In this chapter you will learn multiplication tables Upto 10 x20.

Let us recapitulate the multiplication tables Upto 10 x 10.

Assignment:- Learn tables 2 to 10 and Do Ex- 5A, Page No. 59, 60,  No. 1 and 2 in your text book.

25/AUGUST/2021

CHAPTER 4 SUBTRACTION

COMBINED OPERATION OF ADDITION AND SUBTRACTION

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Example 1 : Simplify : 4134 + 2039 – 506
Method :

Example 2 : Simplify : 55423 + 15067 – 7643 + 367
Method :

Assignment :- Do Ex- 4D, Page No. 51,52 No. 1 to 12 in your Mathematics-OCB.

23/AUGUST/2021

CHAPTER 4 SUBTRACTION

WORD PROBLEMS

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Assignment :- Do Ex- 4C, Page No. 47,48, No. 16 to 25 in your Mathematics-OCB.

11/AUGUST/2021

CHAPTER 4 SUBTRACTION

WORD PROBLEMS

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WORD PROBLEMS
Example 1 : On the first day of a cricket match, 12498 people came and on the second day 16075 people came. How many people were more on second day ?
Solution : Number of people came on first day = 12498
             Number of people came on second day = 16075
             Number of people more on second day = 16075 – 12498 = 3577

Example 2 : What number must be added to 59235 to get 86435 ?
Solution : Required number = 86435 – 59235 = 27200

Assignment :- Do Ex- 4C, Page No. 47,48, No. 1 to 12 in your Mathematics-OCB.    

04/AUGUST/2021

CHAPTER 4 SUBTRACTION

SUBTRACTION WITH BORROWING

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Check for Subtraction
To check the correction of subtraction, we add the difference to the smaller number and see whether the sum obtained is equal to the greater number. If so the solution is correct.

FINDING THE MISSING NUMBERS

Assignment:- Do Ex 4B, Page No. 45, No. 30 to 40 in your Mathematics-OCB and 41 to 46 in the text book.                                                     

02/AUGUST/2021

CHAPTER 4 SUBTRACTION

SUBTRACTION WITH BORROWING

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With Borrowing

SUBTRACTING ACROSS ZERO

PROPERTY OF SUBTRACTION

Assignment:- Do Ex 4B, Page No. 44,45, No. 1 to 21 in the text book and 22 to 29 in your Mathematics-OCB.     

28/JULY/2021

CHAPTER 4 SUBTRACTION

SUBTRACTION WITHOUT BORROWING

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SUBTRACTION WITHOUT BORROWING
Example 1 : Subtract : 9687 – 6234
Solution :

Example 2 : Subtract : 98768 – 53257
Solution :

Assignment:- Do Ex- 4A, Page No. 41, No. 13 to 21 in the text book and No. 26 to 39 in your Mathematics-OCB.

26/JULY/2021

CHAPTER 4 SUBTRACTION 

SUBTRACTION WITHOUT BORROWING 

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.       

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Assignment:- Do Ex- 4A, page No.40,41, No.1 to 12 in the text book and 22 to 25 in your Mathematics-OCB.   

19/JULY/2021

CHAPTER 3 ADDITION  

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WORD PROBLEMS
Example 1 : Mr. Malhotra earned Rs. 37 390 last year. This year he earned Rs. 41785. What is his total earning in both the years ?
Solution : Mr. Malhotra earned last year = Rs. 37390
Mr. Malhotra earned this year = Rs. 41785
Therefore, total earning in both the years
               = Rs. 37390 + Rs. 41785
               = Rs. 79175

Example 2 : The difference between two numbers is 9485. Find the greater number, if the smaller number is 14085.
Solution : Greater number = Smaller number + difference
              = 14085 + 9485
              = 23570

Assignment:- Do No. 11 to 20, Ex-3D, Page No. 37, 38 in your Mathematics-OCB.

14/JULY/2021

CHAPTER 3 ADDITION  

Word Problems

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Addition : Verbal Sums

Assignment:- Do Ex- 3D, Page No. 37, No. 1 to 10 in your Mathematics-OCB.

12/JULY/2021

CHAPTER 3 ADDITION  

Properties of Addition: 

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PROPERTIES OF ADDITION
Property 1: Two or more numbers can be added in any order, but the sum remains the same. This is called order property of addition.

Assignment- Do Ex- 3C, Page No. 35, No. 1 to 10 in the text book.

07/JULY/2021

CHAPTER 3 ADDITION  

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Addition With Carry Over

Addition of more than two numbers

Assignment:- Do Ex- 3B, Pg No. 33,34 , No. 21 to 32 in your Mathematics-OCB.  

05/JULY/2021

CHAPTER 3 ADDITION  

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ADDITION OF 3-DIGIT NUMBERS

ADDITION OF 4-DIGIT NUMBERS
Addition Without Carry Over

Assignment:-  Do Ex-3A, Pg No. 31 No . 13 to 24 in the text book and No. 25 to 34 in your Mathematics-OCB .      

16/JUNE/2021

CHAPTER 2 NUMBERS UP TO TEN THOUSANDS

Successor and Predecessor 

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ASCENDING AND DESCENDING ORDER

Ascending order means arranging numbers from the smallest number to the greatest number.

Example 1 : Arrange the numbers 3747, 1674, 1528 and 6409 in ascending order.

Solution : Here, 1528 is the smallest number.

The next number greater than 1528 is 1674.

The next numbers in greater order are 3747 and 6409.

So, the required ascending order is

1528 < 1674 < 3747 < 6409

or

1528, 1674, 3747, 6409

Descending order means arranging numbers from the greatest number to the smallest number.

Example 2 : Arrange the numbers 6115, 3242, 8056 and 1789 in descending order.

Solution : Here, 8056 is the greatest number.

The next number smaller than 8056 is 6115.

The next numbers in smaller order are 3242 and 1789.

So, the required descending order is

8056 > 6115 > 3242 > 1789.

or

8056, 6115, 3242, 1789.

PREDECESSOR AND SUCCESSOR OF A NUMBER
1 less than any given number is called the predecessor of that number.

Assignment:- Do No. 11 to 14,Ex 2C, page No. 26 and 27 in the text book. 

14/JUNE/2021

CHAPTER 2 NUMBERS UP TO TEN THOUSANDS

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COMPARING NUMBERS
We have already studied comparison of numbers.
Let us understand the rules to compare numbers.

Comparing numbers having different number of digits :

Example : Which is greater a. 315 or 86 ? b. 3896 or 485 ?

Solution : a. 315 has 3 digits and 86 has 2 digits.

So, 315 > 86

b. 3896 has 4 digits and 485 has 3 digits.

So, 3896 > 485

Comparing numbers with the same number of digits :

Example 1 : Which is greater 8742 or 5125 ?
Solution : We write the numbers as shown below :

Here, 8 is greater than 5. 8 > 5.
So, 8742 > 5125

Example 2 : Compare the numbers 3285 or 3876.
Solution : We write the numbers as shown below :

Here, 2 is less than 8. 2 < 8.
So, 3285 < 3876

Assignment:- Do No. 3 to 10 , Ex-2C, page No. 25,26 in the Mathematics OCB.

09/JUNE/2021

MATHEMATICS CLASS TEST

TIME :- 09:20 AM

07/JUNE/2021

CHAPTER 2 NUMBERS UP TO TEN THOUSANDS

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NUMBERS ON THE ABACUS
Look at the abacus shown on the right. We need 4 spikes to represent the 4-digit number. In the given figure of abacus, starting from the left, the spikes represent thousands, hundreds, tens and ones.

Let us now practice 4-digit numbers both in figures and words.

Assignment:- Do No. 1 to 10 ,Ex- 2B, page No. 20 in the text book and Revise Chapter-1 for Class Test on 09/ June/ 2021.

02/JUNE/2021

CHAPTER 2 NUMBERS UP TO TEN THOUSANDS

Example : Find the place value of the digits in the given numbers :

a. 2458

b. 3085

Solution :

Expanded form and standard form or short form :

To expand means to become more in number/size. When you pull a rubber band, it expands. Let us see, how it works with numbers. When we expand the number, we understand the value of each digit in its position.

See the numbers shown in the place value chart :

Now, begin with the place value of the digit in the thousands place. We expand like this :

Standard form or Short form :

Now, we express expanded form into standard form.

Take the help of place value chart.

COMPARING NUMBERS

We have already studied comparison of numbers.

Let us understand the rules to compare numbers.

Comparing numbers having different number of digits :

Example : Which is greater a. 315 or 86 ? b. 3896 or 485 ?

Solution : a. 315 has 3 digits and 86 has 2 digits.

So, 315 > 86

b. 3896 has 4 digits and 485 has 3 digits.

So, 3896 > 485

Comparing numbers with the same number of digits :

Example 1 : Which is greater 8742 or 5125 ?
Solution : We write the numbers as shown below :

Here, 8 is greater than 5. 8 > 5.
So, 8742 > 5125

Example 2 : Compare the numbers 3285 or 3876.
Solution : We write the numbers as shown below :

Here, 2 is less than 8. 2 < 8.
So, 3285 < 3876

ASCENDING AND DESCENDING ORDER
Ascending order means arranging numbers from the smallest number to the greatest number.

Example 1 : Arrange the numbers 3747, 1674, 1528 and 6409 in ascending order.

Solution : Here, 1528 is the smallest number.

The next number greater than 1528 is 1674.

The next numbers in greater order are 3747 and 6409.

So, the required ascending order is

1528 < 1674 < 3747 < 6409

or

1528, 1674, 3747, 6409

Descending order means arranging numbers from the greatest number to the smallest number.

Example 2 : Arrange the numbers 6115, 3242, 8056 and 1789 in descending order.

Solution : Here, 8056 is the greatest number.

The next number smaller than 8056 is 6115.

The next numbers in smaller order are 3242 and 1789.

So, the required descending order is

8056 > 6115 > 3242 > 1789.

or

8056, 6115, 3242, 1789.

Assignment:- Do No. 8 to 18,Ex-2A, pageNo. 16,17 in the text book.

31/MAY/2021

CHAPTER 2 NUMBERS UP TO TEN THOUSANDS

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We have learnt that

We can show the number 999 as below :

If we add 1 more to 999. We will get smallest 4-digit number as shown below :

FORMING 4-DIGIT NUMBERS
Look at the following :

Similarly, we have

NUMBER NAMES

We know that number names are the numbers written in words. Each number is derived from the name of the place where digits are placed.

Example : Write the number names for the following numerals :

4823, 3475, 7780

Solution :

Number Names

Four thousand eight hundred twenty three

Three thousand four hundred seventy five

Seven thousand seven hundred eighty

Example : Write the numerals for the following number names :

Eight thousand two hundred forty six

Five thousand six

Nine thousand thirty nine

Solution : 8246, 5006, 9039

PLACE VALUE AND FACE VALUE

We know that numbers are made-up of digits.

We also know that place value of a digit depends on its position

in the digits, but the face value of a digit remains unchanged.

Look at the place value chart :

the digit 4 is in thousands place, so its place value is 4 thousands or 4000.

the digit 7 is in hundreds place, so its place value is 7 hundreds or 700.

the digit 8 is in tens place, so its place value is 8 tens or 80.

the digit 6 is in ones place, so its place value is 6 ones or 6.

Assignment:- Do No. 2 to 6 ,Ex- 2A, page No. 14 to 16 in the text book.

28/MAY/2021

CHAPTER 1 REVISION 

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Fraction:-

Geometrical shapes

Assignment:- Do No. 72 to 77 Pg No. 6 in the text book.

24/MAY/2021

CHAPTER 1 REVISION 

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Days of the week after and before 

Convert m into cm and cm into m.

Assignment:- Do No. 67 to 71 Pg No .5 in your Mathematics-OCB.

21/MAY/2021

CHAPTER 1 REVISION 

DIVIDE

1. If a number is divided by 1, the quotient is the number itself.

Examples : 141 ÷ 1 = 141 ; 1145 ÷ 1 = 1145, 15417 ÷ 1 = 15417

2. If a number other than zero is divided by itself, the quotient will be 1.

Examples : 415 ÷ 415 = 1, 3168 ÷ 3168 = 1, 31684 ÷ 31684 = 1

3. If zero is divided by a number (other than zero), the quotient will be zero.

Examples : 0 ÷ 305 = 0, 0 ÷ 1405 = 0 ; 0 ÷ 14145 = 0

4. In a division sum the remainder is always smaller than the divisor.

Example :

We see that remainder 2 is smaller than divisor 7.

5. Every division fact has two multiplication facts to verify it.

Example : In division , 12 ÷ 3 = 4

two multiplication facts are 3 × 4 = 12 and 4 × 3 = 12

6. The product of the divisor and the quotient added to the remainder is always equal to the dividend.

(Divisor × Quotient) + Remainder = Dividend

This helps us to check whether the division is done correct or not.

Example : Divide 45 by 7

Solution :

Verification : (Divisor × Quotient) + Remainder = Dividend

                 (7 × 6) + 3 = 45        42 + 3 = 45              45 = 45

So, the division is correct.

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Assignment:- Do No. 62 to 66 Pg No.5 in your Mathematics-OCB.

17/MAY/2021

CHAPTER 1 REVISION 

MULTIPLY

LET US REVISE

We know that multiplication is repeated addition. To find the sum equal amounts are added repeatedly, we can multiply to find the same result in a much easier and quicker way.

Below are given four groups of flowers with 5 flowers in each group.

How many flowers are there altogether ? We can add 5 + 5 + 5 + 5 = 20

20 flowers in all

MULTIPLICATION TABLES
We have learnt the multiplication tables upto 10 in the previous class. Below we show how multiplication table of 2 can be built up. In the similar way, tables of other numbers can be built up.

Now watch this video for your better understanding:-

Multiplication

Assignment:- Do No. 40, 45 to 58 Pg No. 4 in the text book.

10/MAY/2021

CHAPTER 1 REVISION 

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WORD PROBLEMS ON ADDITION

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WORD PROBLEMS ON SUBTRACTION

Assignment:- Do No. 28 to 38 Pg No. 3 in your Mathematics-OCB.

(Four of them have been done for you)

28. No. of pages in one book =        312

       No. of pages in second book = 469

       No. of pages in third book = +   132 

       Total No. of pages               =      913

Hence, she read 913 pages.

32. No. of eggs sold on Monday=     258

       No.of eggs sold on Tuesday = + 369 

        Total No.of eggs sold            =    627

Hence, he sold 627 eggs.

35. Total No. of nails =   653

       No. of nails used = - 484 

       No. of nails left =      169

Hence, 169 nails were left.

37. Total No.of students =  235

        No. of boys             = -  128

        No. Of girls             =     107

Hence, 107 girls are there.

07/MAY/2021

CHAPTER 1 REVISION 

Ascending and descending order:

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Ascending and Descending order

Comparing Numbers:

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Comparing numbers

Greater or smaller Number:

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Comparing Large Numbers

Assignment:- Do No. 24 and 27  Pg No. 2 and 3 in Mathematics OCB and No. 23, 25 and 26 in the text book.

03/MAY/2021

CHAPTER 1 REVISION 

Let us revise what we have already learnt in the previous class .

2. We can also show the number on the abacus.

3. We can represent the number in three different ways.

4. We can also find the place value and face value of a number.

- In 7 65, the place value of 7 is 7 hundreds or 700.

- In 805, the face value of 5 is 5.

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Write Numbers in Figures and Words

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Expanded Form and Short Form

Assignment:- Complete the following in your Mathematics-OCB.

Do No.  1 ( f to j) ,2 ( f to j) and 5 to 12 from Pg No. 1 and 2.