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Python Arithmetic Operators

An arithmetic operator is a maths sign that works on values. Python uses almost the same signs as school maths.

Add and subtract

Adding and taking away work just like in school maths.

print(7 + 3)
print(7 - 3)

Multiply and divide

Python gives a float answer for every divide.

print(4 * 3)
print(10 / 4)
print(8 / 2)

Floor division

Floor division means divide, then round down to a whole number.

print(17 // 5)

The remainder

The remainder is what is left after you share a number evenly.

print(17 % 5)

Power

A power means you times a number by itself that many times.

print(2 ** 3)
print(3 ** 2)

Brackets change the order

Times is worked out before plus. Brackets can force another order.

print(2 + 3 * 4)
print((2 + 3) * 4)

Example

total = 94
people = 4
share = total // people
left_over = total % people
print("Total:", total)
print("Each person pays:", share)
print("Left over:", left_over)

Key points

  • Operator: a sign that tells Python to do something with one or more values.
  • Use / to divide.
  • The result is always a float, a number with a point.
  • Use // for floor division, which rounds the answer down to a whole number.
  • Use % for the remainder, the amount left over after sharing evenly.
  • Use ** for a power, which means a number times itself.
  • Order inside arithmetic: brackets first, then **, then * and /, then + and -.

In this example, the total bill is 94 and there are 4 people. Python divides 94 by 4 with // and gets 23. It then finds the remainder with % and gets 2. The three print lines show the total, the share, and the left over amount.

Note

Floor division rounds down, even below zero.

So -7 // 2 gives -4, not -3.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Python Playground

Exercise

What does 17 % 5 give?