Nice job! Okay, you may be wondering: how do you tell what the appropriate names of the arguments are for a particular function (e.g. x and digits for round)?

Don't panic! If you ever forget what a function does, what its function arguments are, or how the arguments are named, you can simply type a question mark followed by the name of the function, e.g.:

?round

into your editor, and R will display helpful information for the function. The question mark is known as the help operator.