What is twelve times twelve? Most of us, if we were paying any attention in school, know the answer is a gross – 144.

Okay, then what’s thirteen times thirteen?  Gotcha, didn’t I?  That’s because in our school multiplication tables, we stop at twelve – the last number before the compounds (“three-ten” for “thirteen”) kick in.  This fits a pattern: the number thirteen suffers a bad rap by being associated with superstition. 

Read the rest of this entry »