Numbers & Arithmetic Operators

In Plain English

Computers are fundamentally calculators on rocket fuel. Python comes with full arithmetic support out of the box: addition, subtraction, multiplication, decimal division, floor division, modulo (remainder), and exponents.

The Mental Model

"Standard math operators work just like your school calculator. The extra superpowers are // (floor division: tells you how many whole pizzas everyone gets) and % (modulo: tells you how many slices are left over)."

Deep Dive: How It Works

Basic math: + (addition), - (subtraction), * (multiplication), / (standard division). Note that / always produces a float result in Python 3 (e.g. 10 / 2 gives 5.0).

Floor Division (//): Divides two numbers and chops off any decimal remainder, returning the largest integer (e.g. 7 // 2 gives 3).

Modulo (%): Returns the remainder of division (e.g. 7 % 2 gives 1). Super useful for checking if a number is even (num % 2 == 0) or cycling through items.

Exponentiation (**): Raises a number to a power (e.g. 2 ** 3 is 2 cubed = 8). Note: Python uses ** for powers, not ^ (which is bitwise XOR).

Order of Operations: Python strictly follows PEMDAS (Parentheses, Exponents, Multiplication/Division, Addition/Subtraction). Use parentheses ( ) to clarify your intent.

Syntax Blueprint

result = 10 + 5    # Add (15)
result = 10 // 3   # Floor divide (3)
result = 10 % 3    # Remainder (1)
result = 2 ** 4    # Power (16)

Standard arithmetic symbols with // for integer division and ** for power.

Core Rules to Remember

Division Always Floats: The / operator always returns a float (e.g. 4 / 2 is 2.0).

Modulo for Remainders: % gives you the leftover after division. Great for checking even/odd.

Use ** for Powers: In Python, 3 ** 2 is 9. Do not use 3 ^ 2 for exponents.

Common Beginner Traps & How to Fix Them

Mistake:Using ^ for exponentiation: 2 ^ 3

Why it happens: In math notation ^ means power, but in Python ^ is the bitwise XOR operator (2 ^ 3 = 1).

How to fix: Always use double asterisks ** for power calculations (2 ** 3 = 8).

Pro Tip: You can write large numbers with underscores for readability: one_million = 1_000_000. Python ignores the underscores!

Live Interactive Example

Hit Run Code to see it live

Python Math Showcase

Python 3.12

Output Console

Click "Run Code" to view the rendered output.

How it works: Notice how floor division (//) gave 2 instead of 2.5, and modulo (%) gave 2 as the remainder.

Your Turn: Micro Challenge

No pressure! Edit the starter code below and test your solution with instant feedback.

Micro Exercise

Calculate remaining cookies

You have 23 cookies and want to split them equally among 4 friends.
Use the modulo operator % to calculate and print the remaining cookies.

Sandbox Output

Click "Run & Check" to test your solution.

Finished reading and practicing?