Number System (Decimal Number Conversion)Decimal To Binary The decimal number system (base ten) has ten possible values (0,1,2,3,4,5,6,7,8 or 9) for each place value. In contrast, the binary number system (base two) has two possiblevalues, often represented as 0 or 1 for each place-valueTo convert Decimal to binary we divide the decimal number from 2 until we get 0  and remain is written in front of the number as following example.Then we write the number from below to above as shown in that example. Conversion 

Decimal To Octal  The decimal number system (base ten) has ten possible values (0,1,2,3,4,5,6,7,8 or 9) for each place value. In contrast, the Octal number system (base eight) has eight possiblevalues, often represented as 0,1,2,3,4,5,6,7  for each place-value.To convert octal we divide the given number from 8 and remain part written in front of thedivide number as in the following example and do the same until get 0. Then write the remain number from below to up and that is the octal number for the given decimal number.ex: -

Decimal To HexadecimalIn hexadecimal numbers (Base 16) we can have numbers from 0 to 15 and they are represented in a special way. From 0 to 9 they are written as same and from 10 to 15 we represent it as follows.10 -------- A11 -------- B12 -------- C13 -------- D14 -------- E15 -------- F

and see the following example for more information.