# Multiple Arrays

## Completed Code

```javascript
var mainArray= [[ 68, 47, 85, 22], [86, 75, 30, 9], [482, 829, 147, 643], [3906, 2222, 1337, 4962]];

function largestMultiple(mainArray) {
    return mainArray.map(function(subArray) {
        return Math.max.apply(null, subArray);
    });
}
console.log(largestMultiple(mainArray));
```

## Explanation

Remember the `.map()` method? We use it to apply our function to each of the **subArrays**, the arrays within our **mainArray**.

## Smallest

As we did previously, you can simply replace the `.max()` with `.min()` to get the smallest number from each of the four **subArrays**. I also changed **largestMultiple** to **smallestMultiple** so that the function makes sense.

```javascript
var mainArray= [[ 68, 47, 85, 22], [86, 75, 30, 9], [482, 829, 147, 643], [3906, 2222, 1337, 4962]];

function smallestMultiple(mainArray) {
    return mainArray.map(function(subArray) {
        return Math.min.apply(null, subArray);
    });
}
console.log(smallestMultiple(mainArray));
```

## Ultimate Large

If you wanted to get the **one largest value** between the four arrays, all you need is another `Math.max.apply`.

```javascript
var mainArray= [[ 68, 47, 85, 22], [86, 75, 30, 9], [482, 829, 147, 643], [3906, 2222, 1337, 4962]];

function largestMultiple(mainArray) {
    return mainArray.map(function(subArray) {
        return Math.max.apply(null, subArray);
    });
}
console.log(largestMultiple(mainArray));
console.log(Math.max.apply(null, largestMultiple(mainArray)));
```

**Output**

```javascript
[ 85, 86, 829, 4962]
4962
```

## Ultimate Smallest

Use the same code to get the **one smallest value**, but don't forget to replace `.max()` with `.min()`. There are a few occurrences of it.

```javascript
var mainArray= [[ 68, 47, 85, 22], [86, 75, 30, 9], [482, 829, 147, 643], [3906, 2222, 1337, 4962]];

function smallestMultiple(mainArray) {
    return mainArray.map(function(subArray) {
        return Math.min.apply(null, subArray);
    });
}
console.log(smallestMultiple(mainArray));
console.log(Math.min.apply(null, smallestMultiple(mainArray)));
```

**Output**

```javascript
[ 22, 9, 147, 1337 ]
9
```