Basic arithmetic in Python

Python has seven arithmetic operators. Four of them work as on a calculator; the other three are worth learning early.

The program

a = 15
b = 4

print("a + b  =", a + b)
print("a - b  =", a - b)
print("a * b  =", a * b)
print("a / b  =", a / b)
print("a // b =", a // b)
print("a % b  =", a % b)
print("a ** b =", a ** b)

a + b  = 19
a - b  = 11
a * b  = 60
a / b  = 3.75
a // b = 3
a % b  = 3
a ** b = 50625

How it works

• / is normal division. It always gives a float, even when the answer is whole: 8 / 2 is 4.0.
• // is floor division: it divides and rounds down to a whole number. 15 divided by 4 is 3.75, which rounds down to 3.
• % gives the remainder after division: 4 goes into 15 three times (12), and 3 is left over.
• ** raises to a power: 15 to the power 4 is 15 × 15 × 15 × 15 = 50625.

// and % are used together a lot. For example, 135 minutes is 135 // 60 hours and 135 % 60 minutes: 2 hours and 15 minutes.