# Parentheses with arithmetic

Parentheses in lua (and most programming languages) are used to show that you want something done separately. These are used quite a lot, so I'll cover them here.

Parentheses are the ( and ) characters. Typically, parentheses are used when you want to do something in a specific order. For example, with arithmetic:

```
myNumberWithoutParentheses=5/20/5     --.05
myNumberWithParentheses=   5/(20/5)   --1.25
```

So, what's the difference? Why does one become .05 and the other 1.25?

It's the order!

If you work the "myNumberWithoutParentheses" problem out... this is what you'll get.

PROBLEM: 5/20/5 5/20 = .25 .25/5 = 0.05

With parentheses, however...

PROBLEM: 5/(20/5)

20/5=4 --Remember things in parentheses are solved first. 5/4=1.25

So, like you can see, order matters! If you chose not to use parentheses, you would end up doing this all the time (and I see it all the time):

mass=50 volume=2402 weight=mass*volume acceleration=500/weight

acceleration=500/(50*2402)

Note this is a very basic example. I'm using numbers so it's familiar, but you'll most likely be using variables in lua:

acceleration=500/(mass*volume)

You can have parentheses inside of parentheses if you need to:

weightlimit=500*((3056/20)-1)

In the above example, first the 3056/20 part is solved, then it subtracts 1 off of what the answer is. Then that answer is multiplied by 500.

You can use parentheses to do math in an argument, too!

```
function myFunc(number)
Msg("number is "..number.."\n")
end

myFunc( (20*5)-6 ) --number is 94
```

Anyway, that's how you use parentheses with math in lua!

You can give it a try if you want:

```
end

--No parentheses

--Parentheses

--Parentheses in parentheses
```

Save it as parentheses.lua and load it up in GMod!