Decimal, Binary, Octal, and Hex Numbers

There are two other number systems that are used in conjunction with binary; they are called octal and hexadecimal.If a programmer was writing or reading code they would use octal and hexadecimal as a shorthand way of representing binary numbers, because binary numbers can be long, confusing and difficult to read.Octal is base 8, uses the characters 0 to 7 and when using it, binary values are interpreted in groups of three. Hexadecimal is base 16, uses the characters 0 to 9 and A to F and when using it, binary values are interpreted in groups of four.
It is important to state that computer systems can only understand binary. Octal and hexadecimal are used because it is easier to convert binary to and from octal and hexadecimal than decimal.
The following table shows all four number systems together, decimal, octal, hexadecimal and binary. The yellow highlighted sections show the octal grouping.


This is table show us the different between Decimal number , Binary
number Octal number and Hex Numbers .           

Now you know different between Decimal number , Binary number Octal
number and Hex Numbers .

There is tow questions pleas answer in the comment .

- what is the different between Decimal number , Binary number Octal
number and Hex Numbers ?
- What is the important in this table ?