In addition to the simple arithmetic operators, R supports a variety of functions (and custom ones can be created or installed via third-party packages). Functions represent various operations with the data, stored in this way to be easily available for frequent usage.

A simple example of a function is sqrt() which returns a square root of a value. The value is given in parentheses after the function’s name.

Functions may take:

• one value: sqrt(9)
• multiple values: log(8,2) 
• named arguments: round(1.448, digits=2)

Functions may be nested inside each other: round(sqrt(33), digits=2) In such cases, R starts with the inner-most function and proceeds until it reaches the outer-most one.

If you are ever not sure how a function works, you can type its name preceded by ?, e.g. ?plot. This will open the help page of that function, explaining how it is used.