computations like in simple equations, interest and others. You just choose a computation that is easier to memorize.

      I talk about fractions because these kinds of questions are included in IQ tests.  Maybe after about ten years you have already forgotten how to solve fractions and this memorization could help you remember while taking an IQ test
for a job application. 

Trial and Error List

      You don't have to memorize these.  Just try to understand these so you can come up with these on your own. For example if you understand that 1/2 + 1/2 is really equal to 1      or 1/2 + 1/4 is really equal to 3/4 (common sense answers) then you don't