Microsoft Excel can be used as a calculator. The following example shows subtraction. You can use other symbols to add, multiply, divide, and perform other calculations.

1. Double-click on a cell to begin editing it. Type a formula for subtraction and use cell references.
2. Press "Enter" or "Return" on the keyboard to commit the changes to the cell. Then click on the cell again. This will place a small square at the bottom right of the cell.
3. Drag the formula across multiple cells. Move the cursor over the small square so it turns into a very small + symbol.
4. Click, hold, and drag that square to apply the formula to other cells.