JavaScript provides three methods to round a number to the nearest integer, round up or round down. All these are static methods of the `Math` object that you can access directly to round numbers.

1. `Math.round()` — Rounds a number to the nearest integer. If the fraction value is 0.5 or higher, round up.
2. `Math.ceil()` — Rounds up to the nearest integer.
3. `Math.floor()` — Rounds down to the nearest integer.
``````Math.round(5.287) // 5
Math.round(5.87)  // 6

// Rounds up
Math.ceil(5.33)   // 6

// Rounds down
Math.floor(5.87)  // 5
``````

To round a number to 2 decimal places, you need to do a bit of calculation, as shown below:

``````const num = Math.round(5.87456 * 100) / 100

console.log(num) // 5.87
``````

Alternatively, you can use the `toFixed()` method to round a number to 2 decimal places in JavaScript. The `toFixed()` method rounds and formats the number to 2 decimal places:

``````const num = 5.87456

const str = num.toFixed(2)
console.log(str) // 5.87
``````

The `toFixed()` method takes the number of digits after the decimal point as input and returns a string representation of the number.

To convert the string back to a floating point number, you can use the `parseFloat()` method or the `Number()` constructor:

``````const num = 5.87456

const str = num.toFixed(2)
console.log(str) // 5.87
console.log(typeof str) // string

const final = parseFloat(str)
console.log(final) // 5.87
console.log(typeof final) // number

const final2 = Number(str)
console.log(final2) // 5.87
console.log(typeof final2) // number
``````