Divisibility Rule for 6

Problem

Checking divisibility by 6 requires checking both 2 and 3 separately.

Solution

Number must be even AND sum of digits divisible by 3.

Benefit

Combines two simple rules for quick divisibility check.

Example

Is 426 divisible by 6?
Even? Yes (ends in 6)
Digit sum: 4+2+6=12, 12÷3=4 ✓
Yes, divisible by 6!

Is 534 divisible by 6?
Even? Yes
Digit sum: 5+3+4=12, 12÷3=4 ✓
Yes!