Arithmetic operators

You have already used +, -, * and /. Python has three more arithmetic operators. Here they all are:

Integer division and the remainder

// divides and rounds the result down to a whole number: it tells you how many times one number fits into another. % gives what is left over. Together they answer questions such as "how many full boxes, and how many items left":

>>> 17 // 5
3
>>> 17 % 5
2

5 fits into 17 three times, which makes 15, and 2 is left over. Here the same idea turns minutes into hours and minutes:

minutes = 135
hours = minutes // 60
rest = minutes % 60
print(f"{minutes} minutes is {hours} h {rest} min.")

135 minutes is 2 h 15 min.

The remainder is also a quick test for even numbers: an even number divided by 2 leaves nothing, so 14 % 2 is 0, while 15 % 2 is 1. That comes in handy with the conditions at the end of this part.

Powers

** raises a number to a power: 2 ** 3 is 2 * 2 * 2.

>>> 2 ** 3
8
>>> 5 ** 2
25
>>> 10 ** 6
1000000

Watch out: in Python, ^ is not a power. It's a different operator that this course doesn't need, so 2 ^ 3 gives a wrong answer without any error message:

>>> 2 ^ 3
1