What is 13 mod 9?

How to compute 13 mod 9?

The simplest approach is to use the "mod" operator (often denoted as "%" in many programming languages), but you could do it manually in the following way:

$\mathrm{Remainder}=N-(M\times \lfloor \frac{N}{M}\rfloor )$

(where N is the dividend, M is the divisor and $\lfloor \frac{N}{M}\rfloor$ represents the integer part of the quotient)

1. 13 / 9 = 1.4444444444444
2. ⌊1.4444444444444⌋ = 1 (We only keep the integer part)
3. 9 × 1 = 9
4. 13 - 9 = 4 (Subtracting gives us the remainder)

In short: 13 − (9 × ⌊13 / 9⌋) = 4

Is 13 divisible by 9?

A number is said to be divisible by another number, if the remainder of the division is zero.

Given that the result of 13 mod 9 is 4, this indicates that dividing 13 by 9 leaves a remainder of 4. Therefore, no, since the remainder isn't zero, 13 is not divisible by 9.