Useful if you want to display a total somewhere else
Excel Hack: Copy Formula Without Changing Cell References (or Without File References)
When you copy a cell that contains a formula, you will notice that the cell references in the formula also move a corresponding number of cells across and down. This type of cell reference is called a relative reference.
When we copy (Ctrl + C) and paste (Ctrl + V) the formula from the image above into another cell, you will see that the cell references change from column B to column D. So the total is different.
To prevent Excel from changing cell references when you copy cells, you must use absolute references. To create an absolute reference, insert a dollar sign ($) before both parts of the cell reference in the formula you want to freeze, as shown in the following image.
