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. Tap on a cell to begin editing it.
2. Tap on the formula bar to open the keyboard. Select the number keyboard if necessary. Type the = symbol.
3. Tap a cell reference as desired. Type the - symbol. Tap another cell reference as desired.
4. Tap the checkmark icon to confirm your edits to the cell.