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There are two 2️⃣ types of numbers in modern JavaScript:


Ordinary numbers in JavaScript are stored in the 64-bit IEEE-754 format, also called double precision floating point numbers. These are the numbers we will use most often. Integers are not considered a separate type of numbers. In addition to floating point numbers, the numeric data type also includes three character values: Infinity, -Infinity, and NaN (non-number).



Numbers make it possible to work with integers of arbitrary length. They are rarely needed and are used in cases where you need to work with values ​​outside the maximum safe integer value Number.

Any number, even a decimal fraction with a lot of decimal places, is never quoted.

You can use four types of numeric literals: decimal, binary, octal, and hexadecimal. Since the last three are used quite rarely, we will omit their detailed description πŸ–ŠοΈ, but the curious can get acquainted with them here.


Be careful when using leading zeros! This means you don't need to put zero before the decimal number.

0888 // 888 is treated as decimal
0777 // treated as non-strict octal (511 decimal)


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  1. MDN web docs
  2. Code for Teens: The Perfect Beginner's Guide to Programming, Volume 1: Javascript - Jeremy Moritz
  4. Integer arithmetic

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