What Are Formulas in Excel?
Math. Excel 2013 is really good at it, and it’s what makes Excel more than just data storage. Even if you hated math in school, you might still like Excel because it does the math for you.
In Excel, you can write math formulas that perform calculations on the values in various cells, and then, if those values change later, you can see the formula results update automatically. You can also use builtin functions to handle more complex math activities than you might be able to set up yourself with formulas.
A formula is a math calculation, like 2+2 or 3(4+1). In Excel, a formula can perform calculations with fixed numbers or cell contents.
That capability makes it possible to build complex worksheets that calculate loan rates and payments, keep track of your bank accounts, and much more.
In Excel, formulas are different from regular text in two ways:

Formulas begin with an equal sign, like this: =2+2.

Formulas don’t contain text (except for function names and cell references). They contain only symbols that are allowed in math formulas, such as parentheses, commas, and decimal points.