Information and Communication Technology

Decimal to Binary

A given integer decimal number can be converted to its equivalent binary number by performing the following steps :

1. Divide the number by 2.
2. Write the quotient below the number and take it as a new number.
3. Write the remainder in a separate column, termed as remainder column.
4. Repeat steps 1 to 3 until new number becomes ‘0’
5. Obtain the required binary number by writing the digits of remainder column from bottom to top.

Example 1: (25)₁₀ = (. )₂ Remainder column

2	25
2	12	1
2	6	0
2	3	0
2	1	1
	0	1

Thus (25)₁₀ = (11001) ₂

Example 2 : (42)₁₀ = (.) ₂

Remainder column

2	42
2	21	0
2	10	1
2	5	0
2	2	1
2	1	0
	0	1

Hence , (42)₁₀ = ( 101010 ) ₂