Learnearn.uk » IGCSE Computer Science Course » Binary Addition

Before we look at how binary addition works, it’s best to have a review of how denary addition works! Watch the quick video below for a review.

As you can see, denary addition works by adding up the digits in the column and if the result is 10 or higher then you carry the left digit over. As always you start from the right hand side and work your way to the left.

Binary addition is super easy once you understand the basics and follow the same rules as normal denary addition.

Binary addition works in the same manner, only with binary if the result is 2 or 3(10 or 11 in binary form!) you carry the 1 over to the next column.

## Overflow

### Binary Overflow

When we add two binary numbers together we might end up with a number larger than the space available in which to store it. This is known as binary overflow and will result in binary overflow and the left most digit(the most significant bit) will usually be discarded.

So how to do computers actually perform binary addition? We they do so using a combination of logic circuits. These logic circuits combine together to make half and full adder circuits and its using these circuits that the computer is able to perform binary addition.

Watch the video below if you would like to see exactly how these circuits work!