When two single bits are added together, the addition of “0 + 0”, “0 + 1” and “1 + 0” results in either a “0” or a “1” until you get to the final column of “1 + 1” then the sum is equal to “2”. So when adding binary numbers, a carry out is generated when the “SUM” equals or is greater than two (1+1) and this becomes a “CARRY” bit for any subsequent addition being passed over to the next column for addition and so on. Binary Addition follows these same basic rules as for the denary addition above except in binary there are only two digits with the largest digit being “1”.
The adding of binary numbers is exactly the same idea as that for adding together decimal numbers but this time a carry is only generated when the result in any column is greater or equal to “2”, the base number of binary. This carry is then added to the result of the addition of the next column to the left and so on, simple school math’s addition, add the numbers, and carry. When each column is added together a carry is generated if the result is greater or equal to 10, the base number. From our maths lessons at school, we learned that each number column is added together starting from the right-hand side and that each digit has a weighted value depending upon its position within the columns.
