Divisibility Rule for 4

Problem

Testing divisibility by 4 for large numbers requires division.

Solution

Check only the last two digits. If they form a number divisible by 4, the whole number is.

Benefit

Instantly test any number for divisibility by 4.

Example

Is 5,328 divisible by 4?
Check last 2 digits: 28
28 ÷ 4 = 7 ✓
Yes!

Is 7,862 divisible by 4?
Check last 2 digits: 62
62 ÷ 4 = 15.5 ✗
No!