Finally, you can use Mixed Cell References which simply means that a cell reference contains both a relative cell reference and an absolute cell reference. So, instead of having $B$1 (which is absolute), a mixed cell reference can look like $B1 or B$1. In this case, only the number or letter following the dollar sign (S) remains absolute, or unchanged.
Changing a Cell Reference From Relative or Absolute or Mixed
Select the cell that contains the formula you want to copy
Press F2 to edit the formula (Or, you can use the Formula Bar)
Position your cursor in the middle of a cell reference (if your reference is B1, the cursor should be blinking in between the B and the 1)
Press F4 (you can continue to press F4 until you achieve the desired Absolute, Mixed or Relative Cell Reference)