- Formula Basics
- Summarizing Data Quickly
- Elements of Formulas
- Entering Formulas
- Determining the Order of Operations
- Understanding Cell References
- Using Cell References
- Understanding Comparison Operators
- Using Comparison Operators
- Understanding Functions
- Using Functions
- Copying and Moving Formulas
- Handling Errors

## Using Functions

A function can be one of several elements in a formula, or it can be the only element in a formula. When you build a formula,
you don’t type the function names yourself—you use the *function browser* to insert them. The function browser lets you flick through Numbers’ entire library of functions. When you find the function
you want, Numbers inserts it into your formula, including gray-oval argument placeholders. Placeholders for optional arguments
are a lighter gray than those of required arguments.

**To insert a function in a formula:**

- In the formula bar, position the insertion point where you want the function to appear or, to replace an existing function, tap its name to select it.
- Tap the
**functions**key on the keyboard and do one of the following:- To access all Numbers’ functions, tap Categories, tap a category, and then tap a function . (To see every function, tap the All category.)
- To access a function that you’ve used recently, tap Recent and tap a function .
- To get help with a function, tap next to its name . After you finish reading, tap the back button in the top-left corner of the help window to return to the list of functions,
and then tap a function.
Numbers inserts the function and its arguments placeholders in the formula bar.

- In the formula bar, tap each argument placeholder and do one of the following and :
- To insert a cell reference, tap a cell or drag across a cell range.
- To insert a nested function, tap the
**functions**key. - To insert an arithmetic or comparison operator, tap an operator key on the formula keyboard. To switch between the operators,
tap the
**&≤≠**or**()+÷**key. - To insert a number, tap the number keys on the formula keyboard.
- To insert text, tap the
**“abc”**key. - To insert a date, time, or duration, tap the key.
- To insert a Boolean value, tap the
**true/false**key. - To omit an optional argument, leave its placeholder as is. Or, to delete the placeholder, tap the placeholder to select it, tap it again, and then tap Cut in the pop-up menu.