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Python Math Module

The math module is a module that holds maths helpers. Square roots, rounding, and pi all live in the math module.

Square roots and powers

sqrt() undoes squaring. pow() raises a number to a power.

import math

print(math.sqrt(16))
print(math.pow(2, 3))

Round down and round up

floor() drops down to the whole number below. ceil() jumps up to the whole number above.

import math

print(math.floor(3.7))
print(math.ceil(3.2))

The pi value

pi is a value in math, not a function. You do not call it with brackets.

import math

print(math.pi)

Shared factors and factorials

gcd() finds the biggest number that divides both inputs. factorial() multiplies a number by every whole number below it.

import math

print(math.gcd(12, 18))
print(math.factorial(5))

Some helpers need no import

abs() and max() are built in. They work with no import line.

print(abs(-7))
print(max(3, 9))

Example

import math

radius = 5
area = math.pi * math.pow(radius, 2)
print(f"Circle area: {area:.2f}")
hyp = math.sqrt(math.pow(3, 2) + math.pow(4, 2))
print(f"Hypotenuse: {hyp}")
print(f"Area rounded down: {math.floor(area)}")
print(f"Area rounded up: {math.ceil(area)}")

Key points

  • Use import math to use the math module
  • Maths helpers such as sqrt() and pi sit ready in the math module.
  • Use math.sqrt() to get the square root of a number
  • Use math.floor() and math.ceil() to round down and up
  • math.pi holds the value of pi

In this example, the program reports on a circle and a triangle. It finds the circle area with math.pi and math.pow(). It prints that area with two decimal places. Then it finds the hypotenuse with math.sqrt(). Last, it rounds the area down with math.floor() and up with math.ceil().

Note

math.sqrt() always gives a float.

Even math.sqrt(16) gives 4.0, not 4.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Python Playground

Exercise

Which line gives the square root of 9?