AC = A*C .when two variables are beside each other like "AC" I must multiply the two together,
unless told otherwise with a + - / etc sign.
(I'm just trying to show you I understand this. Am I correct?).

I've re-read the algebra section and I must be missing something because I now don't understand the red
part of the formula below (is it called a formula ? ).

F + E(1-F) + (1-F)(1-E)

= 1 - E - F + EF . Where did the plus sign come from.

I'm going to take a guess here and say
I must add the EF on the end because I took away EF from E in the blue part of the formula? But I thought this rule only applied to equations.