I will try to explain this the best I can.

I want to multiple a series of cells say C4:T4 by a specific percent, then
with that product I want to subtract it from the original number, so it
would
be some thing like this:

100*.03= 3 then 100-3 = 97

That "97" is what I need to be replaced in each cell. I have no idea how
to
do this at all. If someone could give me some guidance that would be
great.

You are asking to physically replace the values you have with their
percentage reduction, right? And that percentage value is going to be the
same for each cell, right?

Okay, try this. Put 0.97 (1 minus the percentage value) in a cell somewhere;
then select that cell and press Ctrl+C (or click Edit/Copy from Excel's menu
bar); next select all of the cells you want to do this calculation to; then
click Edit/PasteSpecial from Excel's menu bar; select Multiply from the
Operation section of the dialog box that appeared and then click the OK
button. You can now press Esc to unselect the cell with the 0.97 in it and
then clear it.

Rick