You can add a formula to any cell in a spreadsheet by typing an equal sign (=) followed by the name of the function. Auto-suggest will show a box displaying the name and syntax of the formula you're building.
A function used in the same cell with another function is called a nested function. When functions are combined, Google Sheets will calculate the innermost function first. The nested function is contained in parentheses and is used as one of the components of the surrounding function.
For example, let's say you want to calculate the absolute value of a sum of several numbers in the cell range A1:A7. To calculate the sum of these numbers, you would enter '=SUM(A1:A7)' into a cell.
To calculate the absolute value of this sum, you need to nest the sum formula within absolute value formula. To calculate both formulas in a single cell, enter '=ABS(SUM(A1:A7))' into the cell. Note that the =SUM() function is performed first and is used as a component in the =ABS() function.
When you reference other cells in a formula, we highlight those cells in contrasting colors to help you more easily build a formula. When you click on the cell that contains a completed formula, you'll also see these cells highlighted.
Learn more about functions and formulas in our comprehensive list of functions.