Basic Math in Python

Unlike the previous guide, we're going to use a Python shell to run the commands. A shell is simply an interface for accessing some service, in this case Python.

Python ships with a shell by default. To open the Python shell, use the following:

python3

You should shell a Python prompt that looks something like this:

Python 3.6.5 (default, Mar 30 2018, 06:41:53)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

Here are the operators we'll cover in this guide:

Each of these operators will be covered in the following steps. To gain familiarity with the Python shell as well as arithmetic operators, open a Python shell and practice using each operator.

Chances are, you've encountered this one before. In case you haven't, it's the process of finding the sum of two or more numbers.

>>> 2 + 2
4

>>> 100 - 30
70

>>> 10 * 3
30

>>> 40 / 10
4.0

Notice here that the result is not 4. It's 4.0. Python 3 uses true division (as opposed to Python 2, which uses floor division). This means the result will always be a floating point number representing the fractional result. See the different:

Python 2

>>> 1 / 2
0

Python 3

>>> 1 / 2
0.5

Related to the division operator, this operator gives us the remainder of a division operation.

>>> 10 % 3
1

>>> 2 ** 8
256

This operator gives us what we expect from the division operator in Python 2. It performs the division operation and returns an integer, chopping off any trailing decimals.

>>> 10 // 3
3