Cell Formula reference to cell Based On third Cell Content
 

I want to build a formula in one cell that calls a second based on the
numeric value in a third.

Specifically, Say the frst cell is F10. I want it to look up the number in
F1, and then
if F1=1, F10=E9*something
if F1=2, F10=D9*something
if F1=3, F10=C9* something
etc.