# round down javascript with code examples

JavaScript provides several built-in methods for rounding numbers, one of which is the `Math.floor()` method. This method rounds a number down to the nearest integer.

For example, consider the following code:

```let num = 5.7;
let rounded = Math.floor(num);
console.log(rounded); // Output: 5
```

In this example, the variable `num` is set to 5.7, and the `Math.floor()` method is used to round it down to the nearest integer, which is 5. This result is then stored in the variable `rounded` and logged to the console.

Another example,

```let num = -5.7;
let rounded = Math.floor(num);
console.log(rounded); // Output: -6
```

In this example, the variable `num` is set to -5.7, and the `Math.floor()` method is used to round it down to the nearest integer, which is -6.

It's worth noting that the `Math.floor()` method can also be used on other data types, such as strings. For example:

```let num = "5.7";
let rounded = Math.floor(num);
console.log(rounded); // Output: 5
```

In this example, the variable `num` is a string, but the `Math.floor()` method still correctly converts it to a number and rounds it down.

You can also use the `Math.floor()` method in combination with other mathematical operations. For example:

```let num = 5.7;
let rounded = Math.floor(num * 10) / 10;
console.log(rounded); // Output: 5.7
```

In this example, the variable `num` is first multiplied by 10, and then passed to the `Math.floor()` method to round it down to the nearest integer. The result is then divided by 10 to get the original decimal value rounded down.

In conclusion, the `Math.floor()` method is a simple and efficient way to round numbers down to the nearest integer in JavaScript. It can be used on a variety of data types and in combination with other mathematical operations for more advanced functionality.

In addition to `Math.floor()`, JavaScript also provides several other built-in methods for rounding numbers.

The `Math.ceil()` method rounds a number up to the nearest integer. For example:

```let num = 5.2;
let rounded = Math.ceil(num);
console.log(rounded); // Output: 6
```

The `Math.round()` method rounds a number to the nearest integer, with ties rounded to the nearest even integer. This is also known as "round half to even" or "banker's rounding." For example:

```let num = 5.5;
let rounded = Math.round(num);
console.log(rounded); // Output: 6
```

The `Math.trunc()` method removes the decimal part of a number, effectively rounding it down to the nearest integer towards zero. For example:

```let num = 5.9;
let rounded = Math.trunc(num);
console.log(rounded); // Output: 5
```

It's worth noting that the `Math.trunc()` method has been introduced in ECMAScript 6, it might not be supported in some old browsers. A simple polyfill for this method can be:

```if (!Math.trunc) {
Math.trunc = function(x) {
return x < 0 ? Math.ceil(x) : Math.floor(x);
}
}
```

Another approach for rounding numbers is to use the `toFixed()` method, which rounds a number to a specified number of decimal places. For example:

```let num = 5.6666;
let rounded = num.toFixed(2);
console.log(rounded); // Output: 5.67
```

In conclusion, JavaScript provides several built-in methods for rounding numbers, including `Math.floor()`, `Math.ceil()`, `Math.round()`, `Math.trunc()` and `toFixed()`. Each method has its own specific use case and it is important to choose the appropriate method for your specific needs.

## Popular questions

1. What is the function of the `Math.floor()` method in JavaScript?
• The `Math.floor()` method rounds a number down to the nearest integer.
1. How would you use the `Math.floor()` method to round a decimal number down to the nearest integer in JavaScript?
• The `Math.floor()` method can be used by passing a decimal number as an argument. For example:
```let num = 5.7;
let rounded = Math.floor(num);
console.log(rounded); // Output: 5
```
1. How would you use the `Math.floor()` method to round a negative decimal number down to the nearest integer in JavaScript?
• The `Math.floor()` method works the same way for negative decimal numbers as it does for positive decimal numbers. For example:
```let num = -5.7;
let rounded = Math.floor(num);
console.log(rounded); // Output: -6
```
1. Can the `Math.floor()` method be used on other data types, such as strings in JavaScript?
• Yes, the `Math.floor()` method can be used on other data types, such as strings. For example:
```let num = "5.7";
let rounded = Math.floor(num);
console.log(rounded); // Output: 5
```
1. How can you use the `Math.floor()` method in combination with other mathematical operations in JavaScript?
• The `Math.floor()` method can be used in combination with other mathematical operations. For example:
```let num = 5.7;
let rounded = Math.floor(num * 10) / 10;
console.log(rounded); // Output: 5.7
```

In this example, the variable `num` is first multiplied by 10, and then passed to the `Math.floor()` method to round it down to the nearest integer. The result is then divided by 10 to get the original decimal value rounded down.

### Tag

Rounding Posts created 2498

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