Divisibility

Question 1

What number is divisible by 8?

Answer 1

Whose last THREE digits is divisible by eight

Question 2

What number is divisible by 5?

Answer 2

Whose last digit is either 5 or 0.

Question 3

What number is divisible by 4?

Answer 3

Whose last TWO digits is divisible by four

Question 4

What number is divisible by 2?

Answer 4

Whose last digit is even

Question 5

Rule of divisibility by 3

Answer 5

A number is divisible by 3 if the sum of its digits is divisible by 3.

Question 6

Rule of divisibility by 9

Answer 6

A number is divisible by 9 if the sum of its digits is divisible by 9.

Question 7

The Rule of divisibility by 6

Answer 7

a number is divisible by 6 if it is divisible by 2 and 3

Question 8

Rule of divisibility by 11

Answer 8

(sum of digits in odd places) - (sum of digits in even places) = a number that is divisible by 11.
The sum of digits in 1st, 3rd and 5th places (odd places: 121,792) = 1+1+9 = 11
The sum of digits in 2nd, 4th and 6th places (even places: 121,792) = 2+7+2 = 11

Question 9

The rule of divisibility for 7

Answer 9

1) Multiply the number of hundreds the number has by 2.
2) Add the remaining two digit number.
3) If the result is divisible by 7, the original number is divisible by 7.

5040 is divisible by 7:

1) There are 50 “hundreds” in 5040. Multiply 50 by 2 to get 100.
2) Add the remaining two-digit number 40 to get 140.
3) 140 is divisible by 7, so 5040 is divisible by 7