sum using names
If it does not work!
The feature may have been switched off on your computer.
You can switch it on by using Tools, Options, Calculation, Accept Labels in Formula.
You can use the names typed at the top of columns or side of rows in calculations simply by typing the name into the formula.
Try this example: Go to cell C16 and then enter the formula =SUM(jan)
The result will show. This formula can be copied to D16 and E16, and the names change to Feb and Mar.