Page 334 - Excel 2013 All-in-One For Dummies

316 Copying Formulas
Figure 1-8:
Using an absolute address in the formula to calculate monthly percentage of the total.
However, because you want to copy this formula across to the range C10:J10 to calculate the percentages for the eight months (May through December), you need to alter the relative cell references in the last part of the formula
in cell K8 so that this cell reference with the nine-month production total remains unchanged in all your copies.
You can start to understand the problem caused by adjusting a relative cell reference that should remain unchanged by just thinking about copying the original formula from cell B10 to C10 to calculate the percentage for May.
In this cell, you want the following formula that divides the May production total in cell C8 by the nine-month total in cell K8:
=C8/K8
However, if you don’t indicate otherwise, Excel adjusts both parts of the for- mula in the copies, so that C10 incorrectly contains the following formula:
=C8/L8
Because cell L8 is currently blank and blank cells have the equivalent of the value 0, this formula returns the #DIV/0 formula error as the result, thus indi- cating that Excel can’t properly perform this arithmetic operation. (See Book III, Chapter 2 for details on this error message.)
To indicate that you don’t want a particular cell reference (such as cell K8 in the example) to be adjusted in the copies that you make of a formula, you change the cell reference from a relative cell reference to an absolute cell reference. In the A1 system of cell references, an absolute cell reference con- tains dollar signs before the column letter and the row number, as in $K$8. In the R1C1 notation, you simply list the actual row and column number in