In Excel, you are able to perform mathematical operations using formulas. All formulas must begin with an = sign, for example, if you typed =3*5 in a cell and hit the enter key, 15 would appear in the cell. Take this a step further and do a more complicated calculation using the AutoSum button, for example =SUM(B2*C2).
You can also highlight columns or rows of data and select the AutoSum button to calculate data.
If you select the Formulas tab at the top of the page, Excel will display an entire library of useful formulas. These are broken down by subject, such as Financial or Math & Trig.