The Math.round()
function returns the number rounded to the nearest integer. That is, 3.87 is rounded to 4 and 3.45 is rounded to 3.
Example
let number = 3.87;
// round the number to nearest integer
let roundedNumber = Math.round(number);
console.log(roundedNumber);
// Output: 4
Math.round() Syntax
The syntax of the Math.round()
function is:
Math.round(x)
round()
, being a static method, is called using the Math
class name.
Math.round() Parameters
The Math.round()
function takes in:
- x - A number
Return value from Math.round()
Math.round()
returns the value of the number rounded to the nearest integer as follows:
- If the fractional portion > 0.5, x is rounded to integer with higher absolute value.
- If the fractional portion < 0.5, x is rounded to integer with lower absolute value.
- If the fractional portion = 0.5, x is rounded to the next integer in the direction of +∞.
Example: Using Math.round()
// using Math.round()
var num = Math.round(1.8645);
console.log(num); // 2
var num = Math.round(10.49);
console.log(num); // 10
var num = Math.round(4.5);
console.log(num); // 5
var num = Math.round(-4.5);
console.log(num); // -4
// Returns 0 for null
var num = Math.round(null);
console.log(num); // 0
// Returns NaN for non-numeric types
var num = Math.round("JavaScript");
console.log(num); // NaN
Output
2 10 5 -4 0 NaN
Note: Math.round()
returns 0
for null
rather than NaN
.
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