Numbers and Math

Python has two kinds of numbers: integers (whole numbers like 7) and floats (decimals like 3.75). You combine them with math operators.

Arithmetic operators

+ add, - subtract, * multiply
/ divide — always gives a float (10 / 2 is 5.0)
// floor divide — divides and drops the decimal part (7 // 2 is 3)
% modulo — the remainder left over (7 % 2 is 1)
** power (2 ** 3 is 8)

print(10 + 3)
print(10 / 3)
print(10 // 3)
print(10 % 3)

Even when it divides evenly, / produces a decimal number:

print(6 / 3)

That prints 2.0, not 2. Any use of / gives a float — worth remembering when your answer has an unexpected .0 on the end.

round(value, n) rounds a number to n decimal places:

average = 37 / 3
print(average)
print(round(average, 2))

Python follows normal maths order — * and / happen before + and -. Use parentheses when you want a different order:

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

Add two lines: print a floor-divided by b, then print the remainder of a divided by b.

a = 17
b = 5
# add two prints: floor division first, then the remainder

Expected output

3
2

Practise this in the free Python course, where every exercise checks your code instantly.