> For the complete documentation index, see [llms.txt](https://mudassirs46.gitbook.io/network-fundamentals/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mudassirs46.gitbook.io/network-fundamentals/number-history.md).

# Number History

**A Network Engineer must know 3 Numbering System:**

* **Decimal (Base 10) (0-9)**
* **Binary (Base 2) (0-1)**
* **Hexadecimal (Base 16) (0-15, A-F)**
* In the olden days, people discovered that counting on sticks would not be efficient hence they invented the Base 10 method (counting on fingers) as humans have only 10 fingers.
* This method led to the invention of the Number system 0-9.
* The calculation would look like this…

  | Decimal Number |
  | -------------- |
  | 0              |
  | 1              |
  | 2              |
  | 3              |
  | 4              |
  | 5              |
  | 6              |
  | 7              |
  | 8              |
  | 9              |
* This even led to the invention of the power (or exponent) in the calculation.
* As it is in ones place value hence there can be no other combination. Hence they added another digit (the tens-place value column to increase the number & the combination).

## Reference:

* <https://www.khanacademy.org/math/algebra-home/alg-intro-to-algebra/algebra-alternate-number-bases/v/number-systems-introduction>
* <https://www.udemy.com/course/cisco-ccent-icnd1-100-105-complete-course-sims-and-gns3/learn/lecture/18891518#overview>