Page 57 - ICSE Math 6

Solution: Let’s put * in the blank space:

Sum of all
digits at odd Sum of all Difference
S. No. Number places from digits at even of Value of *
the right, i.e., places from the A and B
‘A’ right, i.e., ‘B’
(a) 7,*4,891 1 + 8 + * = 9 + * 9 + 4 + 7 = 20 20 – (* + 9) For the given
= 11 – * number to be
divisible by 11
we must have
11 – * = 11
∴ * = 0
(b) 4,97,6*3 3 + 6 + 9 = 18 * + 7 + 4 = 11 + * 18 – (11 + *) For the given
= 7 – * number to be
divisible by 11
we must have
7 – * = 0
∴ * = 7

EXERCISE 4.2

1. Using divisibility tests, determine which of the following numbers are divisible by 2.

(a) 4,56,739 (b) 8,97,078 (c) 9,99,992
2. Using divisibility tests, determine which of the following numbers are divisible by 3.
(a) 2,34,693 (b) 98,745 (c) 4,56,386
3. Using divisibility tests, determine which of the following numbers are divisible by 4.

(a) 76,892 (b) 98,576 (c) 6,57,482
4. Using divisibility tests, determine which of the following numbers are divisible by 5.
(a) 3,46,789 (b) 8,76,590 (c) 9,87,605
5. Using divisibility tests, determine which of the following numbers are divisible by 6.

(a) 71,124 (b) 78,651 (c) 67,85,910
6. Using divisibility tests, determine which of the following numbers are divisible by 8.
(a) 88,364 (b) 27,314 (c) 6,75,416
7. Using divisibility tests, determine which of the following numbers are divisible by 9.

(a) 7,89,651 (b) 7,57,900 (c) 87,65,433
8. Using divisibility tests, determine which of the following numbers are divisible by 10.
(a) 5,67,895 (b) 5,40,980 (c) 6,78,500
9. Using divisibility tests, determine which of the following numbers are divisible by 11.

(a) 4,55,400 (b) 10,00,001 (c) 91,30,825
10. Write the smallest digit in the blank space of each of the following numbers so that the number
formed is divisible by 3.
(a) 3,2__,386 (b) 5__,945

41