I have a formula:

(H - R)(L - H - C)

What the formula means is not relevant.

I need to find the total when H and L are constant and

R = 1 and C = 1
R = 1 and C = 2
R = 1 and C = 3
R = 2 and C = 1
R = 2 and C = 2
R = 2 and C = 3
R = 3 and C = 1
R = 3 and C = 2
R = 3 and C = 3

Obviously there is an easy way of showing this apart from writing it out that many times. I know I probably need to use the Sigma notation.

If anyone could help I would be very greatful

I hope this makes sense!!

Dan