CODEWITHSUNDEEP
javascriptnumbers
Bhupi
Bhupi

Reputation: 2969

'e' in javascript numbers

I need to understand the following:

when I type 4e4 in Google Chrome's console it returns 40000.

Can anyone help me to understand what is e in javascript numbers and what is the algorithm working for this?

Thanks in advance

Upvotes: 33

Views: 22346

Answers (4)

ptvty
ptvty

Reputation: 5664

As this question is specifically about JavaScript I think it's good to have the examples from MDN here:

0e-5   // 0
0e+5   // 0
5e1    // 50
175e-2 // 1.75
1e3    // 1000
1e-3   // 0.001
1E3    // 1000

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Numbers_and_dates#exponentiation

Upvotes: 1

Mayday
Mayday

Reputation: 5146

4*10^4

If the number was 4e5 this would be equal to 4*10^5

etc.

Upvotes: 8

andrgolubev
andrgolubev

Reputation: 885

4e4 is a floating-point number representation. It consists of:

  1. Sign - S(+ or -)
  2. Mantissa - M(some number, normalized: 1.x where x is some sequence of digits)
  3. Exponent - E(represents a power of 10 that is Mantissa(M) multiplied with)

It is also a way of how floating-point numbers are stored on the system. For instance, for single-precision we get: single-precision floating-point number representation

Together, it gives us:

-1^S * M * p^E where p is the basis of the numerical system

So, in common sense, p can be anything so that 4e4 could be also 4 * 5^4 if p == 5

As we usually work with decimal values p is equal to 10

And as was answered before, 4e4 == 4 * 10^4 (as 4 is a decimal value in this case)

Upvotes: 17

BJ Black
BJ Black

Reputation: 2531

'e' in a number like that is the same as 'times 10 to the power of'

3.2e6 is 3.2x10^6

Upvotes: 14

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