Divisibility by 8

Divisibility by 8 is determined by looking at the hundreds digit. If it's even, you only have to check the number formed by the last two digits for divisibility by 8. 


Example 468. The 4 is even, so we check 68. 68 is not divisible by 8. 
Example 672. The 6 is even, so we check 72. 72 is divisible by 8. Hence 672 is divisible by 8.


If the hundreds digit is odd, it works differently. Here we must look at the number formed by the last two digits + 4. If that number is divisible by 8, then the whole number is divisible by 8. Let's take an example with an odd hundreds digit. 


Example 568. The 5 is odd, so we look at 68+4 (=72). 72 is divisible by 8, hence the number 568 is divisible by 8. 
Example 972. The 9 is odd, so we look at 72+4 (= 76). 76 is not divisible by 8, hence 972 is not divisible by 8.