In this lesson, we’re diving into Python’s built-in math helpers and some important math-related modules. You’ll learn how to handle numbers the Pythonic way!

🔹 1. Built-in Functions for Numbers

👉 abs(): Absolute Value

The abs() function returns the absolute value of a number — basically, how far it is from zero, without caring if it’s positive or negative.

print(abs(5))     # 5
print(abs(-5))    # 5
print(abs(-3.8))  # 3.8

💡 Absolute value just removes the minus sign if it exists.

👉 round(): Rounding Numbers

The round() function takes a number and rounds it to the nearest whole number (by default).

print(round(0.12))   # 0
print(round(4.5))    # 4 or 5, depending on the Python version
print(round(7.9))    # 8

You can also specify a second argument to tell Python how many decimal places you want:

print(round(0.12, 1))   # 0.1
print(round(4.567, 2))  # 4.57

🔹 2. Useful Math Modules in Python

Python also gives you powerful tools in the form of math-related modules. You need to import them before using.

🧮 math module

This is the most commonly used module for general math stuff.

import math

print(math.sqrt(16))      # 4.0
print(math.pi)            # 3.141592653589793
print(math.sin(math.pi))  # 0.0 (close enough!)

Use it when working with:

  • square roots
  • trigonometry
  • logarithms
  • constants like pi and e

🔢 cmath module

The cmath module is for complex numbers. If your math needs imaginary numbers like 1 + 2j, this is your friend.

import cmath

print(cmath.sqrt(-1))   # 1j

💰 decimal module

The decimal module helps you work with precise decimal numbers — great for money and finance!

from decimal import Decimal

print(Decimal('0.1') + Decimal('0.2'))   # 0.3 (not 0.30000000000000004)

🧮 fractions module

The fractions module is great when you want to work with fractions/rational numbers instead of floats.

from fractions import Fraction

print(Fraction(1, 3))             # 1/3
print(Fraction(1, 3) + Fraction(1, 6))   # 1/2

✅ Practice Questions

Try solving these to test your understanding:

  1. What will abs(-10.5) return?
  2. Use round() to round 3.14159 to 2 decimal places.
  3. Use math.sqrt() to find the square root of 64.
  4. Add Decimal('0.1') and Decimal('0.2'). Why is this better than using normal floats?
  5. What is the result of adding Fraction(2, 5) and Fraction(3, 10)?
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