# 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.

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` . |

## 12.5.2. Check Your Understanding¶

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`

?

`Math.floor(-3.87)`

`Math.random(-3.87)`

`Math.round(-3.87)`

`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);
``` |

- A random number between 0 and 9.
- A random number between 0 and 10.
- A random number between 1 and 9.
- 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);
``` |

- A random number between 0 and 9.
- A random number between 0 and 10.
- A random number between 1 and 9.
- A random number between 1 and 10.