ok, here's the scenario:

Column A = number of sales
Column B = gross per sale

depending on number of sales, the percentage of commission increases (i.e.
10 sales = 30% commission, 20 sales = 40% commission) I want to be able to
plug numbers in the columns and have my commission be totalled at the cell I
have designated.

If someone could show me how to do it I would greatly appreciate it.

thanks