Wait, wait! Don’t groan yet! It’s really simple math! Like, pluses and minuses and stuff! No long division, and no integrating differential equations, I promise! That’s a later chapter!

*If this is your first time here, I recommend looking at the first lesson. Starting there and going through the rest of the lessons will prepare you to go through this more advanced lesson!*

Open up the PyCharm Python Console (see SSP#0). You’ll notice that the lines you type on start with “>>>”. That’s normal. You’ll also notice that I’ll start things I want you to type with “>>>”. That’s also normal. You should not, however, type extra “>>>”. That’s not normal. The line after the “>>>” is the output line. That’s also also normal. You’ll also notice that I say also too much. That’s also not normal.

Now some math! Type:

```
>>> 1 + 1
2
```

Yay! Math! See? Easy stuff. Now try:

```
>>> 1 - 1
0
```

And it works like that with all the numbers, including negatives!

```
>>> 3 + 5 - 10
-2
>>> 111 * 7777
863247
```

Now a variable! A variable is a name for a piece of data, like a number.

`>>> bananas = 3`

We call that “assigning `3`

to `bananas`

.” You may have noticed that it didn’t have any output. That’s because the number `3`

went “into” the variable `bananas`

. Now if we type:

```
>>> bananas
3
```

There’s our 3!

We can also do:

```
>>> apples = 10 - 6
>>> apples
4
```

There, we subtracted `6`

from `10`

, then assigned that (`4`

) to `apples`

! It will always completely figure out the right side of the `=`

before assigning the value (in this case `10 - 6`

).

You can also do math on variables that contain numbers:

```
>>> apples + 10
14
>>> apples # Notice here how apples did not change!
4
>>> apples = apples + 10 # Now it will change, because we assigned it again!
>>> apples
14
```

In addition to adding numbers to variables, you can add variables to other variables:

```
>>> apples + apples
28
>>> apples
14
>>> fruits = bananas + apples
>>>fruits
17
```

Whew! Math is done. That wasn’t so bad, was it?

Questions or comments? Let me know below!