Binary numbers in JavaScript

What is a binary number?

A binary number is a number expressed in the base-2 (binary) numeral system. An integer, (let’s say 5, for example) is in decimal (base 10) form. But 5 can be converted to it’s binary (base 2) form. The binary form of 5 is 101.

What’s the connection?

A binary number (like 101) is a number that is written with 0s and 1s. Each 0 in a binary number represents 0. Each 1 in a binary number represents 2^n, where n is the column position of that 1. For example, the binary number 101 translates to 2^2 + 0 + 2^0 (4 + 0 + 1 = 5). The column position, n, for the rightmost column is 0. The column position, n, for the second-to-last column is 1. The column position, n, for the third-to-last column is 2 and so on and so forth.

Let’s try another number. The binary form for the decimal number 7 is 111. This translates to 2^2 + 2^1 + 2^0 (4 + 2 + 1 = 7).

One more. The binary form the decimal number 27 is 11011. This translates to 2^4 + 2^3 + 0 + 2^1 + 2^0 (16 + 8 + 0 + 2 + 1 = 27).