Question

If 18 is a multiple of a number, then 18 is divisible
by that number.
Give reason

Answer 1

A number that is divisible by 18 must be divisible by both 2 and 9.

The inverse is also true:

A number that is divisible by both 2 and 9 must be divisible by 18.

Therefore, we just have to test for both divisibility by 2 and 9.

If a number is divisible by 2, its last digit must be even.

If a number is divisible by 9, the sum of all its digits must be a multiple of 9.

If a number passes both tests, then it will surely be divisible by 18.

.

Answer 2

Answer:

A number that is divisible by 18 must be divisible by both 2 and 9. A number that is divisible by both 2 and 9 must be divisible by 18 also

I hope it helped.