Arithmetic operators are used in mathematical expressions in the same way that they are used in algebraic equations.
Modulo, division and multiplication come next and are evaluated from left to right.
Addition and subtraction come later and are evaluated from left to right.
Spaces don't do sht unless you f-ed up somewhere lol.
As for prefix and postfix increments/decrements, they have been discussed for over the past decade. Just search the forum.