"I avoid mental arithmetic because I tend to drop decimals, misremember the rules of algebra, and other heinous sins"

Fast and accurate arithmetic can trained with any number of software packages. Why not give it a try? I did and it worked for me.

"Altruistic behavior: An act done without any intent for personal gain in any form. Altruism requires that there is no want for material, physical, spiritual, or egoistic gain."

"Personal gain" is a very vague concept so this is not the best definition. Is the warm fuzzy feeling I get after helping someone personal gain? ( it sounds like "Spirtual" or "egoistic" gain to me.) Is fufilling any desire whatsoever personal gain? ( If so it' hard to see that there are very many things which are not selfish.) These questions need answering just as much as the intial question so I don't think this quote is a satisfactory answer.