Arithmetic & Basics
Basic

Divisibility by 3

A number is divisible by 3 if its digit sum is.

Formula

digit sum divisible by 3\text{digit sum divisible by 3}

Variables

digitsNumber digits

Example

123: 1+2+3=6 ✓

Did You Know?

A number is divisible by 3 exactly when its digits add up to a multiple of 3 — a trick that works in any base minus one.

divisibility