Page 43 - ICSE Math 5

Multiplication and tion and
Multiplica

4
Division
Division

Learning Outcomes

Students will be able to learn:
 multiplication of large numbers.
 division of 3-digit and 4-digit numbers by a 2-digit number.
 estimating the product and quotient of numbers.
 framing and solving word problems based on multiplication and division.

We have already learnt multiplication and division in the previous classes. Let’s perform these
two number operations on large numbers in this chapter.
Multiplication

We know that multiplication is repeated addition of the same number. In multiplication, the
multiplicand and the multiplier are multiplied to get the product.

The numbers to be multiplied are first arranged in columns and then multiplied by starting from
the ones column.
Multiplication Tables

We know how to construct tables up to 10 using various methods like repeated addition, skip
counting and by adding 1 to 10.
Now let’s learn how to construct multiplication tables of 11 to 20 using three different methods.
Let’s review it with an example.
Example 1: Construct the table of 11 using the method of repeated addition.

Solution: Repeated addition
To construct the table of 11 using this method, we need to add each number 11
times repeatedly.

1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 = 11 or 11 × 1 = 11
2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 = 22 or 11 × 2 = 22
3 + 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3 + 3 = 33 or 11 × 3 = 33
4 + 4 + 4 + 4 + 4 + 4 + 4 + 4 + 4 + 4 + 4 = 44 or 11 × 4 = 44

5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 = 55 or 11 × 5 = 55
6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 = 66 or 11 × 6 = 66
7 + 7 + 7 + 7 + 7 + 7 + 7 + 7 + 7 + 7 + 7 = 77 or 11 × 7 = 77
8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 = 88 or 11 × 8 = 88

9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 = 99 or 11 × 9 = 99
10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 = 110 or 11 × 10 = 110

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