Align the binary numbers by place value
Start adding from the rightmost bit
Add each pair of bits
If the sum is 0 or 1, write that bit
If the sum is 2, write 0 and carry 1
If the sum is 3, write 1 and carry 1
Continue moving left one bit at a time
Add any carried 1 to the next column
If a carry remains after the leftmost bit, write it at the front
Check the result by comparing place values from right to left