######
In the movie Stand and Deliver (Warner Brothers 1988), Edward James Olmos,
portraying mathematics teacher Jaime Escalante, confronts Chuco, a defiant
gang member, during Olmos's class at Garfield High School in East Los Angeles.
Escalante was using a well-known
finger-multiplication trick: multiplying by nines by counting on his fingers.

To see this technique, click on the following:

Finger Multiplication

Paul Horrell shows how to expand this technique of multiplying by 9s up to any number less than 99. To see this method, click here:

Extension of Finger Multiplication