A binary number can be readily converted to a decimal number, just by adding their positional values. Let us have a shortcut formula to convert a decimal number to binary. It is called as Division-Remainder technique. The steps to be followed are,
i) Divide a decimal number by 2 and write down its quotient and remainder.
ii) Divide the quotient further by 2 and write down its quotient and remainder.
iii) Repeat this process until the quotient becomes zero.
iv) Arrange the remainders from bottom to top and get the required binary number.
Let us convert the decimal number 18 to binary.
10 0 10
b i nary
We can interconvert any other systems just following the above steps. The base 2 may be replaced by other bases.