The basic mathematical function keys are as follows:
+ for addition
– for subtraction
* for multiplication
/ for division
All formulas must begin with an operator such as + – =
If you enter a formula into a cell without a mathematical operator, Excel treats the formula as text. Eg. 5+5 will not result in 10, but instead, the characters 5+5 will appear in the cell. The formula +5+5 will result in 10.
When referencing two cells in a formula, it is best to use their cell address instead of the cell contents. Eg. +A1+B1 or =A1+B1 instead of +5+5
The result of a formula appears in the cell; the formula bar displays the formula when the cell is selected.