How do you substitute a cell reference with the formula contained with the referenced cell?

For instance I have cell B7 which has the formula =B5*B4*B3

cell D11 has the formula =B7*C7

I want the computer to go through and substitute so cell D11 reads =(B5*B4*B3) * C7

I know I could go through and do this by hand, but I have 5 layers of nested formulas to get to the actual data. I am a novice excel user and it seems to me that there should be some included something to go through and do all of these nested substitutions without making any mistakes, like I will. Can anyone help me?