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