Math

Math is one of JavaScript's global or standard built-in objects, and can be used anywhere you can use JavaScript. It contains useful constants like π and Euler’s constant and functions such as floor(), round(), and ceil().

In this article, we'll look at examples of many of those functions. But first, let's learn more about the Math object.

Example

The following example shows how to use the Math object to write a function that calculates the area of a circle:

function calculateCircleArea(radius) {
  return Math.PI * Math.pow(radius, 2);
}

calculateCircleArea(1); // 3.141592653589793

Math Max

Math.max() is a function that returns the largest value from a list of numeric values passed as parameters. If a non-numeric value is passed as a parameter, Math.max() will return NaN.

An array of numeric values can be passed as a single parameter to Math.max() using either spread (...) or apply. Either of these methods can, however, fail when the amount of array values gets too high.

Syntax

Math.max(value1, value2, value3, ...);

Parameters

Numbers, or limited array of numbers.

Return Value

The greatest of given numeric values, or NaN if any given value is non-numeric.

Examples

Numbers As Parameters

Math.max(4, 13, 27, 0, -5); // returns 27

Invalid Parameter

Math.max(4, 13, 27, 'eight', -5); // returns NaN

Array As Parameter, Using Spread(…)

let numbers = [4, 13, 27, 0, -5];

Math.max(...numbers); // returns 27

Array As Parameter, Using Apply

let numbers = [4, 13, 27, 0, -5];

Math.max.apply(null, numbers); // returns 27

Math Min

The Math.min() function returns the smallest of zero or more numbers.

You can pass it any number of arguments.

Math.min(7, 2, 9, -6);
// returns -6

Math PI

Math.PI is a static property of the Math object and is defined as the ratio of a circle’s circumference to its diameter. Pi is approximately 3.14149, and is often represented by the Greek letter π.

Examples

Math.PI \\ 3.141592653589793

More Information:

MDN

Math Pow

Math.pow() returns the value of a number to the power of another number.

Syntax

Math.pow(base, exponent), where base is the base number and exponent is the number by which to raise the base.

pow() is a static method of Math, therefore it is always called as Math.pow() rather than as a method on another object.

Examples

Math.pow(5, 2); // 25
Math.pow(7, 4); // 2401
Math.pow(9, 0.5); // 3
Math.pow(-8, 2); // 64
Math.pow(-4, 3); // -64

Math Sqrt

The function Math.sqrt() returns the square root of a number.

If a negative number is entered, NaN is returned.

sqrt() is a static method of Math, therefore it is always called as Math.sqrt() rather than as a method on another object.

Syntax

Math.sqrt(x), where x is a number.

Examples

Math.sqrt(25); // 5
Math.sqrt(169); // 13
Math.sqrt(3); // 1.732050807568
Math.sqrt(1); // 1
Math.sqrt(-5); // NaN

Math Trunc

Math.trunc() is a method of the Math standard object that returns only the integer part of a given number by simply removing fractional units. This results in an overall rounding towards zero. Any input that is not a number will result in an output of NaN.

Careful: This method is an ECMAScript 2015 (ES6) feature and thus is not supported by older browsers.

Examples

Math.trunc(0.1)   //  0
Math.trunc(1.3)   //  1
Math.trunc(-0.9)  // -0
Math.trunc(-1.5)  // -1
Math.trunc('foo') // NaN

Math Ceil

The Math.ceil() is a method of the Math standard object that rounds a given number upwards to the next integer. Take note that for negative numbers this means that the number will get rounded “towards 0” instead of the number of greater absolute value (see examples).

Examples

Math.ceil(0.1)  //  1
Math.ceil(1.3)  //  2
Math.ceil(-0.9) // -0
Math.ceil(-1.5) // -1

Math Floor

Math.floor() is a method of the Math standard object that rounds a given number downwards to the next integer. Take note that for negative numbers this means that the number will get rounded “away from 0” instead of to the number of smaller absolute value since Math.floor() returns the largest integer less than or equal to the given number.

Examples

Math.floor(0.9)  //  0
Math.floor(1.3)  //  1
Math.floor(0.5)  //  0
Math.floor(-0.9) // -1
Math.floor(-1.3) // -2

An application of math.floor: How to Create a JavaScript Slot Machine

For this exercise, we have to generate three random numbers using a specific formula and not the general one. Math.floor(Math.random() * (3 - 1 + 1)) + 1;

slotOne = Math.floor(Math.random() * (3 - 1 + 1)) + 1;
slotTwo = Math.floor(Math.random() * (3 - 1 + 1)) + 1;
slotThree = Math.floor(Math.random() * (3 - 1 + 1)) + 1;

Another example: Finding the remainder

Example

5 % 2 = 1 because
Math.floor(5 / 2) = 2 (Quotient)
2 * 2 = 4
5 - 4 = 1 (Remainder)

Usage

In mathematics, a number can be checked even or odd by checking the remainder of the division of the number by 2.

17 % 2 = 1 (17 is Odd)
48 % 2 = 0 (48 is Even)

Note Do not confuse it with modulus % does not work well with negative numbers.

More math-related articles: