Skip to content

Learn

Number Theory

Level 8 / realistic untimed

Divisibility (all small rules)

3 visual steps / divisibility rule

1. Digit sum

divisible? 918 by 91. Digit sum9 + 1 + 8 = 18.19 + 1 + 8 = 18218 divisible by 93answer yes
9 + 1 + 8 = 18.

9 + 1 + 8 = 18.

2. Multiple of 9

divisible? 918 by 92. Multiple of 918 divisible by 9.19 + 1 + 8 = 18218 divisible by 93answer yes
18 divisible by 9.

18 divisible by 9.

3. Answer yes

divisible? 918 by 93. Answer yesanswer yes. Read answer answer yesanswer yes.
answer yes.

answer yes.

Practice Level 8

Use the visible move, then type only when the answer is clear.

Start Level