Any programming language includes many built-in functions that can be used in arithmetic expressions.
To use additional functions, you often have to connect additional libraries.

For example, the most commonly used standard mathematical functions and their writing in Python

 abs(i) module of integer n
 math.fabs(x) modulus of a real number x
 math.sqrt(x) the square root of the real number x
 math.pow(x,y) computes x to the power of y

Remember that the function argument is always written in brackets.
For these functions to work, you need to connect an additional mathematical library (module).
You can do this by adding a line at the beginning of the program

import math

A detailed description of the functions that this module contains can be found on official site with documentation on the Python language