Python Numbers

int and float

int holds whole numbers of any size; float holds decimal numbers.

a = 10
b = 2.5
big = 2 ** 100
print(type(a), type(b))
print(big)

<class 'int'> <class 'float'>
1267650600228229401496703205376

Arithmetic operators

print(7 + 2)
print(7 - 2)
print(7 * 2)
print(7 / 2)   # true division
print(7 // 2)  # floor division
print(7 % 2)   # remainder
print(7 ** 2)  # power

9
5
14
3.5
3
1
49

Note the difference between / (always returns a float) and // (floor division).

Floating-point precision

Floats are stored in binary, so some decimals can't be represented exactly:

import math
print(0.1 + 0.2)
print(0.1 + 0.2 == 0.3)
print(math.isclose(0.1 + 0.2, 0.3))
print(round(2.675, 2))

0.30000000000000004
False
True
2.67

Compare floats with math.isclose(), and use the decimal module (or integer cents) for money.