Numbers and conversion

Python has two main number types: int for whole numbers and float for decimals. Regular division / always returns a float, so even 6 / 3 gives 2.0.

For integer division there are two operators: // returns the quotient with the fraction dropped, and % returns the remainder. So 135 // 60 gives 2 and 135 % 60 gives 15. You'll use the two together whenever you split a quantity into units, like minutes into hours or items into pages.

Everything that comes from forms and files arrives as text, even when it looks like a number, so "19.90" * 3 doesn't multiply anything: it repeats the string three times. Convert the text to a number first with float() or int(), and when you want to go back from a number to text, use str().

Keep in mind that computers store decimals approximately, so 19.9 * 3 gives 59.699999999999996. That isn't a bug in Python, it's how computers store fractions. When you want to display the result, round it with round(x, 2).