Which numbers in the below are divisible by 4 24 171 162 1387 70 72 967 1432?

Answer 1

Only 24, 72 and 1432 are divisible by 4.

All multiples of 4 are even, so 171, 1387 and 967 are not divisible by 4.

To test for being divisible by 4 either:

a) The last two digits (as a number) must be divisible by 4; or (easier)

b) Add the ones (last) digit to the tens digit; if this sum is divisible by 4 then so is the original number. If repeated on the sum until a single digit remains, then this single digit must be 4 or 8 for the original number to be divisible by 4.

24: 4 + 2x2 = 8 → divisible by 4

162: 2 + 2x6 = 14 → 4 + 2x1 = 6 → not divisible by 4

70: 0 +2x7 = 14 → 4 + 2x1 = 6 → not divisible by 4

72: 2 + 2x7 = 16 → 6 + 2x1 = 8 → divisible by 4

1432: 32 → 2 + 2x3 = 8 → divisible by 4