Compare 2 cells to calculate a third cell

I am just getting into excel vba.
Is there a way to compare 2 cell values , and if a condition is met do a calculaion in a third cell?

I want to do this for a range of cell from top to bottom
Thanks for any help you can proivide.
I thave the excel vba for dummies but I think I am too dumb to fully understand it

Thanks