You should probably also know what mod actually does. (In the examples % is mod)
Mod is similar to division, but it tells you how much is left after dividing but not going into decimal places. (You probably did this in elementary school with long division, you write the answer, "r" then the remainder)
For example:
5 % 2 = 1
when you divide 2 into 5 (5/2) you get two with a remainder of one
4 % 2 = 0
When you get zero back from mod(ulo), that means the numerator goes evenly into the denominator leaving no remainder.
The most useful use of this (I've found) is alternating between two procedures.
Say you have a counter x, and you want to put out "a" then "b" for the number of times the user enters (printing "a" is once, "b" is the second)
let count = user input
let x = 0 (current count)
for x -> count do:
if (x mod 2) is 0: print "a"
or else: print "b"
(end for)
There's no point trying to use something if you have no idea what it does
