# `Math.ceil`, `floor`, and `trunc` Examples¶

## `Math.ceil`¶

The general syntax for this method is:

```Math.ceil(number)
```

This method rounds a decimal value UP to the next integer (hence the ceiling reference in the name). Integer values remain the same.

`ceil` also operates on arrays (see below).

Numerical strings can also be evaluated, but should be avoided as a best practice.

Example

 ```1 2 3 4 5 6 7``` ```console.log(Math.ceil(8.88)); console.log(Math.ceil(8.1)); console.log(Math.ceil(-3.9)); console.log(Math.ceil(5)); ```

Console Output

```9
9
-3
5
```

## `Math.floor`¶

The general syntax for this method is:

```Math.floor(number)
```

This method is the opposite of `Math.ceil`. It rounds a decimal value DOWN to the previous integer. Integer values remain the same.

`floor` also operates on arrays (see below).

Numerical strings can also be evaluated, but should be avoided as a best practice.

Example

 ```1 2 3 4 5 6 7``` ```console.log(Math.floor(8.88)); console.log(Math.floor(8.1)); console.log(Math.floor(-3.9)); console.log(Math.floor(5)); ```

Console Output

```8
8
-4
5
```

## `Math.trunc`¶

The general syntax for this method is:

```Math.trunc(number)
```

This method removes any decimals and returns only the integer part of `number`.

`trunc` also operates on arrays (see below).

Numerical strings can also be evaluated, but should be avoided as a best practice.

Example

 ```1 2 3``` ```console.log(Math.trunc(8.88)); console.log(Math.trunc(10.000111)); ```

Console Output

```8
10
```

Note

At first glance, `Math.floor` and `Math.trunc` appear to do exactly the same thing. However, a closer look shows that the two methods treat negative numbers differently.

Console Output

## Combine with `map`¶

When combined with the map array method, `ceil`, `floor`, and `trunc` will operate on each entry in an array. The syntax for this is:

```arrayName.map(Math.method)
```

Example

 ```1 2 3 4 5``` ```let numbers = [-2, 3.33, -4.44, 8.88]; console.log(numbers.map(Math.ceil)); console.log(numbers.map(Math.floor)); console.log(numbers.map(Math.trunc)); ```

Console Output

```[ -2, 4, -4, 9 ]
[ -2, 3, -5, 8 ]
[ -2, 3, -4, 8 ]
```