Decimal Numbers  Binary Numbers 

Decimal numbers consist of combination ten digits or values from 0 to 9 (0,1,2,3,4,5,6,7,8,9).  Binary numbers are formed by combination of only 2 digits or values 0 (zero) and 1 (one). 
The radix for decimal number is 10 i.e all the digits in a decimal number are expressed in terms of powers of 10.  The radix for binary number is 2 i.e all the digits or values in a binary number are expressed in terms of powers of 2. 
Example of decimal number : 25 (Twenty Five)  Example of Binary number : 11001 (Twenty Five) 
Applications
 Applications

Note : Even though decimal numbers and binary numbers are different, the set of rules for addition, subtraction, multiplication and division applicable to decimal numbers is also applicable to binary numbers. But the way the these operations are performed is slightly different which we will learn in detail later.