One of the other tasks required for GCSE computer science is the ability to add two binary numbers up to 8 bits and consider overflow. But starting small might be better

Hopefully this interactive will help.

#### Starting Small

In binary **1 _{2} + 0_{2} = 1_{2} **

(The little 2 denotes using binary or base 2)

But look at the next two additions

**1 _{2} + 1_{2} = 10_{2} **

**1 _{2} + 1_{2} + 1_{2} = 11_{2} **

This means that, in column addition, you will need to carry a bit to the next column!

#### Up to 4 bits

- Make your own numbers by clicking on the digits or set a random question.
- Click on the answer digits on the lower register to set the answer
- Click Check to see if you are correct.

(You can hide the carry digits if necessary)

Try it first with 4 binary digits (4 bits or a nibble)

#### Making it bigger (8 bit)

Once you have mastered this, then try with a whole byte (8 bits)

#### Further investigation

What happens when the answer exceeds 8 bits?

Investigate this overflow…