## Table of contents

## Definition

When you take a look at mathematical formulas most of them usually have alphabets say **x** or **y** in them, and the intention is that anyone using these formulas will replace the **x** and **y**s with actual values. In the programming world functions can be viewed as these formulas and parameters will be the **x** and **y**s.

## Use Cases and Examples

Here is an example of a function in Javascript that adds two parameters together:

```
01: // declaring the function
02: function adder(a, b) {
03: return a+b;
04: }
05:
06: // using the function
07: adder(1,2);
```

What you have above is a function called **adder** that takes two parameters and returns the sum of `a`

and `b`

. The last bit of the code [→] shows how you will use this function.
You will refer to the values you pass in to replace the parameters as arguments [→].

## Summary

Parameters are key to how we end up getting different behaviors out of the same piece of code.

Here is another article you might like 😊 "What Is A Parser?"