Page 67 - ICSE Math 5

Example 11: Check the divisibility of 97,135 by 5 and 10.
Solution: Since the digit at the ones place of 97,135 is 5, it is divisible by 5 but not by 10.

Example 12: Check the divisibility of 83,490 by 6.

Solution: Since the digit at the ones place of 83,490 is 0 (an even number), it is divisible by 2.

Sum of the digits of 83,490 = 8 + 3 + 4 + 9 + 0 = 24
24 is divisible by 3. So, 83,490 is divisible by 3.

Since 83,490 is divisible by both 2 and 3, it is also divisible by 6.

Example 13: Is 9,73,424 divisible by 8? Calculation

Solution: The number formed by the last three digits of the number 5 3
9,73,424 is 424, which is divisible by 8, i.e., 424  8 = 53. 8 4 2 4
So, 9,73,424 is also divisible by 8. – 4 0 
2 4
– 2 4
0

Example 14: Check the divisibility of 79,376 by 11.
Solution: Sum of the digits at odd places of the number 79,376 = 7 + 3 + 6 = 16

Sum of the digits at even places of the number 79,376 = 9 + 7 = 16

Difference = 16 – 16 = 0

Since the difference obtained is 0, 79,376 is divisible by 11.

Top Tip
If two numbers are divisible by another number, then their sum and difference is
also divisible by that number. For example, 12 and 16 are divisible by 4, and their sum
28 and difference 4 is also divisible by 4.

Exercise 5.2

1. Check the divisibility of the following numbers by 3 and 9.

(a) 723 (b) 9,604 (c) 8,325 (d) 4,86,612

2. Check the divisibility of the following numbers by 5 and 10.
(a) 2,685 (b) 9,99,900 (c) 36,412 (d) 25,540

3. Check the divisibility of the following numbers by 11.

(a) 75,691 (b) 2,37,405 (c) 7,986 (d) 45,748

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