Math Object

Math Object

The built-in Math object gives you math constants and functions.

Math constants

Math.PI;    // 3.141592653589793
Math.E;     // 2.718281828459045

Rounding methods

Math.round(4.7);  // 5  (rounds normally)
Math.ceil(4.2);   // 5  (always rounds up)
Math.floor(4.7);  // 4  (always rounds down)
Math.trunc(4.9);  // 4  (removes decimals)

Common functions

Math.pow(2, 3);    // 8
Math.sqrt(16);     // 4
Math.abs(-5);      // 5
Math.max(1, 5, 3); // 5
Math.min(1, 5, 3); // 1

Math.random

Math.random() returns a random number between 0 (included) and 1 (excluded):

Math.random(); // e.g. 0.523473...

Random integers

To get a random whole number between 1 and 10:

Math.floor(Math.random() * 10) + 1;

TL;DR

• Math.PI and Math.E are constants.
• round, ceil, floor, and trunc round numbers.
• pow, sqrt, abs, max, min are common helpers.
• Math.random() returns 0 to just under 1.