# Simple Formulas

You can use formulas in Excel and other spreadsheet programs to add, subtract, multiply, and divide. Use simple Excel formulas to also make cell references.

### Challenge!

- Open an existing Excel workbook. If you want, you can use our practice workbook.
- Create a simple addition formula using
**cell references**. If you are using the example, create the formula in cell** B4** to calculate the total budget. - Try modifying the
**value** of a cell referenced in a formula. If you are using the example, change the value of cell **B2** to $2,000. Notice how the formula in cell B4 recalculates the total. - Try using the
**point-and-click method** to create a formula. If you are using the example, create a formula in cell **G5 **that multiplies the cost of **napkins** by the **quantity** needed to calculate the **total cost**. **Edit** a formula using the formula bar. If you are using the example, edit the formula in cell** B9** to change the **division sign** (**/**) to a **minus** **sign** (**-**).