This was partly covered in an earlier 6/19 post.

If I divide something by 3 the answer is never 0. so how is n % 3 == 0 every a thing to test?

% is divide, right?

== is exactly equal to, right?

what am I missing?

if number % 3():

3 is not a function.

if number % 3 == 0:

now becomes a conditional. If the modulo of a number divided by another number is zero, then the divisor is a factor of the dividend.

if A % B == 0:

# A is evenly divisible by B