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Start your free trial###### ella blue

2,252 Points# error...... var chance = Math.random(0, 20);

var chance = Math.random(0, 20);

```
<!DOCTYPE html>
<html lang="en">
<head>
<title>JavaScript Foundations: The Math Object</title>
<link rel="stylesheet" href="core.css">
<script>
var diameter = 5.75,
a = 17,
b = 42,
c = 1337,
ageIfILiveToYear2100 = (new Date(2100, 0, 1) - new Date(1995, 5, 16, 7, 20)) / (1000 * 60 * 60 * 24 * 365.242);
var circumference = diameter * Math.PI;
var chance = Math.random(0, 20);
/*
The JavaScript Math object has the following
constant (among others):
Math.PI
Approximately 3.14159. Pi (π) is used
to determine the circumference of a circle
given its diameter by multiplying the diameter
by π. Geometery refresher: the circumference
of a circle is the distance around the outside
edge. The diameter is the width of the circle.
The JavaScript Math object also has the following
methods (among others):
Math.random()
Returns a random number between 0 and 1
Math.max(a, b, ...)
Returns the largest value of the passed
arguments
Math.floor(a)
Returns the value of a number rounded down to
the nearest integer
*/
</script>
</head>
<body>
<h1>JavaScript Foundations</h1>
<h2>The Math Object</h2>
<script src="viewer.js"></script>
</body>
</html>
```

## 3 Answers

###### mikes02

Courses Plus Student 16,968 PointsMath.random returns a random number between 0 and 1. So in order to go between 0 and 20 you would have to do:

```
var chance = Math.floor((Math.random() * 20) + 0); // random number between 0-20
var chance = Math.floor((Math.random() * 20) + 1);; // random number between 1-20
```

###### Ken Alger

Treehouse TeacherElla;

The method `Math.random()`

does not accept arguments such as `0, 20`

.

Read more about the function here.

If you are trying to generate a random number between 0 and 20, try:

```
Math.floor(Math.random() * 20) + 0;
```

The `Math.floor(x)`

function returns the largest integer less than or equal to a number `x`

. You would also multiply the random number by the upper limit of your target range and then add your lower target range to it. Obviously if you are going from 0 you don't need to add the zero, but if you wanted 1 to 20, you would replace the 0 in the code with a 1.

Happy coding,

Ken

###### ella blue

2,252 Pointsthanks everyone! :)