# Perform Math Operations in Python

This lesson will introduce arithmetic operations in Python. In addition to basic addition, subtraction, multiplication, and division, you will learn about the differences in division between Python 2 and Python 3.

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This lesson will introduce arithmetic operations in Python. In addition to basic addition, subtraction, multiplication, and division, you will learn about the differences in division between Python 2 and Python 3.

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Math operations in Python are pretty straightforward. We can say 3+4, and it returns a sum. We can do 3-4, same as 3*4, and can even do 3 mod 4. Those all work the same between Python 2 and Python 3.

Division is a little bit different. In Python 2, if I do 3/4, I get 0. It rounds that to an integer. If I wanted to see the complete value, I need to include the period or dot at the end, and it returns 0.75. Let me show you that in Python 3, by actually typing the Python 3 command.

In Python 3, if I do 3/4, I get 0.75. If I wanted that rounded to an integer, I can use double slashes, and that returns 0. This works for variables, too. I can create a variable, a, and set it to 3. I can set b = 4. If I do a+b, it returns 7. If I do a/b, it returns 0.75, or a//b, and it returns 0.

Quick note on naming variables in Python. There are some recommendations here, that they are all in lowercase. We could say sum=3+4, or if there is multiple words, it's recommended that they are separated by the underscore.

Finally, it's recommended that variable names don't start with a number. That would not be a recommended variable name in Python.