Modulus operator nim

You can use the modulus operator like this:

tile mod 9 == 0

Others have suggested using %%, but don't do that. It is a remnant of a time when Nim used to have only signed integers. The operators ending with % like <% are used to handle these signed integers as unsigned ints. Since Nim has had unsigned integers for a while now, simply use the mod operator that is correctly overloaded for all relevant integral types: https://nim-lang.org/docs/system.html#mod,int,int