Page 58 - Math Skill - 4

56 Maths

Write the multiples of 2 in the red circle and multiples of 3 in the green circle.

2 3
2, 4, 6 3
8, 10 9 Absorbing Facts
14, 16 12 15 Multiple of any number is always greater
18
20 21 than or equal to the given number.

Common multiples of 2 and 3

We will observe that the numbers 6, 12 and 18 are the multiples of both 2 and 3.
Therefore, 6, 12 and 18 are the first three common multiples of 2 and 3.

Lowest Common Multiple or LCM

The Lowest Common Multiple (LCM) of given numbers is the smallest common multiple of
these numbers. For example, we find the LCM of 3 and 7 as follows :

Multiples of 3 are 3, 6, 9, 12, 15, 18, 21 , 24, 27, ...

Multiples of 7 are 7, 14, 21 , 28, 35, ...
First common multiple of 3 and 7 is 21. Hence, the LCM of 3 and 7 is 21.

Let us learn through examples.

Let’s Attempt

Example 1: Write first five multiples of 8.
Solution: The first five multiples of 8 are as follows:
8 × 1 = 8 8 × 2 = 16 8 × 3 = 24 8 × 4 = 32 8 × 5 = 40
Thus, 8, 16, 24, 32 and 40 are first five multiples of 8.
Example 2: Is 83 multiple of 9? Example 3: Is 192 a multiple of 6?

Solution: We divide 83 by 9. Solution: We divide 192 by 6.

9 3 2
9 8 3 6 1 9 2
–8 1 –1 8
2 1 2
– 1 2

Since, remainder is not equal to 0. 0
Therefore, 83 is not a multiple of 9.
Since, remainder is equal to 0.
Therefore, 192 is a multiple of 6.

Example 4: Find the LCM of 4 and 6.

Solution: Multiples of 4 are 4, 8, 12 , 16, 20, ...