# 12.5. Math Methods¶

As with strings and arrays, JavaScript provides some built-in methods for the `Math` object. These allow us to perform calculations or tasks that are more involved than simple multiplication, division, addition, or subtraction.

## 12.5.1. Common Math Methods¶

The `Math` object contains over 30 methods. The table below provides a sample of the most frequently used options. More complete lists can be found here:

To see detailed examples for a particular method, click on its name.

Ten Common Math Methods
Method Syntax Description
abs `Math.abs(number)` Returns the positive value of `number`.
ceil `Math.ceil(number)` Rounds the decimal `number` UP to the closest integer value.
floor `Math.floor(number)` Rounds the decimal `number` DOWN to the closest integer value.
max `Math.max(x,y,z,...)` Returns the largest value from a set of numbers.
min `Math.min(x,y,z,...)` Returns the smallest value from a set of numbers.
pow `Math.pow(x,y)` Returns the value of x raised to the power of y (x y).
random `Math.random()` Returns a random decimal value between 0 and 1, NOT including 1.
round `Math.round(number)` Returns `number` rounded to the nearest integer value.
sqrt `Math.sqrt(number)` Returns the square root of `number`.
trunc `Math.trunc(number)` Removes any decimals and returns the integer part of `number`.

Follow the links in the table above for the `floor`, `random`, `round`, and `trunc` methods. Review the content and then answer the following questions.

Question

Which of the following returns `-3` when applied to `-3.87`?

1. `Math.floor(-3.87)`
2. `Math.random(-3.87)`
3. `Math.round(-3.87)`
4. `Math.trunc(-3.87)`

Question

What is printed by the following program?

 ```1 2 3``` ```let num = Math.floor(Math.random()*10); console.log(num); ```
1. A random number between 0 and 9.
2. A random number between 0 and 10.
3. A random number between 1 and 9.
4. A random number between 1 and 10.

Question

What is printed by the following program?

 ```1 2 3``` ```let num = Math.round(Math.random()*10); console.log(num); ```
1. A random number between 0 and 9.
2. A random number between 0 and 10.
3. A random number between 1 and 9.
4. A random number between 1 and 10.