What is the divisibility rule for eight?

Answer 1

A number is divisible by 8 if and only if it is an integer and the last three digits make a number that is divisible by 8.

A general divisibility rule for 2^n where n is an integer is to take the last n digits and if they make a number that is divisible by n then it is divisible by n.

Answer 2

There isn't an especially easy divisibility rule for 8, but because 1,000 divides by 8, you can say any digits greater than the hundreds are irrelevant for divisibility. So to work out if a number is divisible by 8, you only need to look at the last 3 numbers. Divide these numbers by 4, and if the result is even, that means the whole number is divisible by 8.