secrets-of-mental-math-malestrom

Chapter 2
Products of a Misspent Youth:
Basic Multiplication
I probably spent too much time of my childhood thinking about
faster and faster ways to perform mental multiplication; I was
diagnosed as hyperactive and my parents were told that I had a
short attention span and probably would not be successful in
school. (Fortunately, my parents ignored that advice. I was also
lucky to have some incredibly patient teachers in my first few
years of school.) It might have been my short attention span that
motivated me to develop quick ways to do arithmetic. I don’t
think I had the patience to carry out math problems with pencil
and paper. Once you have mastered the techniques described in
this chapter, you won’t want to rely on pencil and paper again,
either.
In this chapter you will learn how to multiply in your head
one-digit numbers by two-digit numbers and three-digit numbers.
You will also learn a phenomenally fast way to square
two-digit numbers. Even friends with calculators won’t be able
to keep up with you. Believe me, virtually everyone will be dumbfounded
by the fact that such problems can not only be done