# Basic arithmetic in Excel

Formulas are the backbone of most advanced calculations within Excel. Think of a formula as an equation — it's a series of steps that lead to a final output. You can tell Excel that you're entering a formula in Excel by starting your input with the equals sign (=). For example, try entering the following into a cell:

`=5+4Output: 9`

Since Excel sees the = sign at the beginning of the line, it realizes that it's being given a formula to calculate. It then sees 5+4 and adds the two numbers together, outputting a final value of 9.

Formulas in Excel use the standard mathematical order of operations to evaluate. As such, operations within formulas are processed in this order:

• Parentheses
• Exponents (^)
• Multiplication (*)
• Division (/)
• Subtraction (-)

Take a look at the following equations, and see whether you can figure out how Excel arrives at the outputs specified:

`=8+4Output: 12`
`=8+4/4Output: 9`
`=(8+4)/4Output: 3`
`=8+4^2Output: 24`
`=(8+4)^2Output: 144`