
Binary Addition. Example 3.
Problem: 100101 + 10101 = ?.
Answer: 100101 + 10101 = 111010.
Explanation:
first column (from the right!) :  1 + 1 = 0 carry 1 
second column :  0 + 0 + 1 (carried) = 1 
third column :  1 + 1 + no carry = 0 carry 1 
fourth column :  0 + 0 + 1 (carried) = 1 
fifth column :  0 + 1 + no carry = 1 
sixth column :  1 + 0 + no carry = 1 
Therefore the answer is 1 1 1 0 1 0!
