Question

Is 234 divisible by 9?

Answer 1

Yes

Explanation:

Any number for which the sum of its digits is `9` (or a multiple of `9`) is divisible by `9`
`color(white)("XXX")2+3+4=9`

Added note

Adding the digits to check divisibility this way works for `9` and for `3`.

For example the digits of `426` sum to `12`, so `426` is divisible by `3` and is not divisible by `9`.