JS ObjectsLesson #87

JavaScript Math Object

The JavaScript Math object allows you to perform mathematical tasks.

The Math Object

The JavaScript Math object allows you to perform mathematical tasks.

The Math object is static.

All methods and properties can be used without creating a Math object first.

Math.PI;

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Math Properties (Constants)

The syntax for any Math property is : Math.*property*.

JavaScript provides 8 mathematical constants that can be accessed as Math properties:

Example

Example Code

javascript
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Math.E        // returns Euler's number

Math.PI       // returns PI

Math.SQRT2    // returns the square root of 2

Math.SQRT1_2  // returns the square root of 1/2

Math.LN2      // returns the natural logarithm of 2

Math.LN10     // returns the natural logarithm of 10

Math.LOG2E    // returns base 2 logarithm of E

Math.LOG10E   // returns base 10 logarithm of E

Math Methods

The syntax for Math any methods is : Math.*method*(*number*)


Number to Integer

There are 4 common methods to round a number to an integer:

Math.round(x)Returns x rounded to its nearest integer
Math.ceil(x)Returns x rounded up to its nearest integer
Math.floor(x)Returns x rounded down to its nearest integer
Math.trunc(x)Returns the integer part of x (new in ES6)

Math.round()

Math.round(x) returns the nearest integer:

Examples

Example Code

javascript
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Math.round(4.6);

Math.ceil()

Math.ceil(x) returns the value of x rounded up to its nearest integer:

Example

Example Code

javascript
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Math.ceil(4.9);

Math.ceil(4.7);

Math.ceil(4.4);

Math.ceil(4.2);

Math.ceil(-4.2);

Math.floor()

Math.floor(x) returns the value of x rounded down to its nearest integer:

Example

Example Code

javascript
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Math.floor(4.9);

Math.floor(4.7);

Math.floor(4.4);

Math.floor(4.2);

Math.floor(-4.2);

Math.trunc()

Math.trunc(x) returns the integer part of x:

Example

Example Code

javascript
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Math.trunc(4.9);

Math.trunc(4.7);

Math.trunc(4.4);

Math.trunc(4.2);

Math.trunc(-4.2);

Math.sign()

Math.sign(x) returns if x is negative, null or positive.

  • If x is positive it returns 1
  • If x is negative it returns -1
  • If x is zero, it returns 0

Example

Example Code

javascript
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Math.sign(-4);

Math.sign(0);

Math.sign(4);
Math.trunc() and Math.sign() were added to JavaScript 2015 - ES6.

Math.pow()

Math.pow(x, y) returns the value of x to the power of y:

Example

Example Code

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Math.pow(8, 2);

Math.sqrt()

Math.sqrt(x) returns the square root of x:

Example

Example Code

javascript
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Math.sqrt(64);

Math.abs()

Math.abs(x) returns the absolute (positive) value of x:

Example

Example Code

javascript
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Math.abs(-4.7);

Math.sin()

Math.sin(x) returns the sine (a value between -1 and 1) of the angle x (given in radians).

If you want to use degrees instead of radians, you have to convert degrees to radians:

Angle in radians = Angle in degrees x PI / 180.

Example

Example Code

javascript
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Math.sin(90 * Math.PI / 180);     // returns 1 (the sine of 90 degrees)

Math.cos()

Math.cos(x) returns the cosine (a value between -1 and 1) of the angle x (given in radians).

If you want to use degrees instead of radians, you have to convert degrees to radians:

Angle in radians = Angle in degrees x PI / 180.

Example

Example Code

javascript
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Math.cos(0 * Math.PI / 180);     // returns 1 (the cos of 0 degrees)

Math.min() and Math.max()

Math.min() and Math.max() can be used to find the lowest or highest value in a list of arguments:

Example

Example Code

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Math.min(0, 150, 30, 20, -8, -200);

Example

Example Code

javascript
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Math.max(0, 150, 30, 20, -8, -200);

Math.random()

Math.random() returns a random number between 0 (inclusive), and 1 (exclusive):

Example

Example Code

javascript
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Math.random();
You will learn more about Math.random() in the next chapter of this tutorial.

The Math.log() Method

Math.log(x) returns the natural logarithm of x.

The natural logarithm returns the time needed to reach a certain level of growth:

Examples

Example Code

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Math.log(1);

Math.E and Math.log() are twins.

Example

Example Code

javascript
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Math.log(10);

The Math.log2() Method

Math.log2(x) returns the base 2 logarithm of x.

Example

Example Code

javascript
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Math.log2(8);

The Math.log10() Method

Math.log10(x) returns the base 10 logarithm of x.

Example

Example Code

javascript
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Math.log10(1000);

Learn More: > Full Math Reference


Interactive Code Examples

JS Example 1

javascript
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JavaScript syntax and algorithm demonstration.
Math.E        // returns Euler's number

Math.PI       // returns PI

Math.SQRT2    // returns the square root of 2

Math.SQRT1_2  // returns the square root of 1/2

Math.LN2      // returns the natural logarithm of 2

Math.LN10     // returns the natural logarithm of 10

Math.LOG2E    // returns base 2 logarithm of E

Math.LOG10E   // returns base 10 logarithm of E

Examples

javascript
Try it Yourself
JavaScript syntax and algorithm demonstration.
Math.round(4.6);

JS Example 3

javascript
Try it Yourself
JavaScript syntax and algorithm demonstration.
Math.ceil(4.9);

Math.ceil(4.7);

Math.ceil(4.4);

Math.ceil(4.2);

Math.ceil(-4.2);

JS Example 4

javascript
Try it Yourself
JavaScript syntax and algorithm demonstration.
Math.floor(4.9);

Math.floor(4.7);

Math.floor(4.4);

Math.floor(4.2);

Math.floor(-4.2);

JS Example 5

javascript
Try it Yourself
JavaScript syntax and algorithm demonstration.
Math.trunc(4.9);

Math.trunc(4.7);

Math.trunc(4.4);

Math.trunc(4.2);

Math.trunc(-4.2);

JS Example 6

javascript
Try it Yourself
JavaScript syntax and algorithm demonstration.
Math.sign(-4);

Math.sign(0);

Math.sign(4);