# Built-in Functions (Functions)

A built-in function is one that you don’t need to install and load a package to use. Some examples include:

`abs()`

returns the absolute value of a number (e.g.,`abs(-2`

))`round()`

, rounds a number (the first argument) to a given number of decimal places (the second argument) (e.g.,`round(12.1123, 2)`

)`sqrt()`

, takes the square root of a number (e.g.,`sqrt(4)`

)`tolower()`

, makes a string all lower case (e.g.,`tolower("HELLO")`

)`toupper()`

, makes a string all upper case (e.g.,`toupper("hello")`

)

Use these built-in functions to print the following items:

- The absolute value of -15.5.
- 4.483847 rounded to one decimal place.
- 3.8 rounded to the nearest integer.
*You don’t have to specify the number of decimal places in this case if you don’t want to, because*`round()`

will default to using`0`

if the second argument is not provided. Look at`help(round)`

or`?round`

to see how this is indicated. `"species"`

in all capital letters.`"SPECIES"`

in all lower case letters.- Assign the value of the square root of 2.6 to a variable. Then round the variable you’ve created to 2 decimal places and assign it to another variable. Print out the rounded value.

*Optional Challenge*: Do the same thing as task 6 (*immediately above*), but instead of
creating the intermediate variable, perform both the square root and the round
on a single line by putting the `sqrt()`

call inside the `round()`

call.

*Expected outputs for Built-in Functions:*

*1*