3.2

# A recap on binary

Before you delve into binary arithmetic, let’s have a quick recap on the binary counting system.

In denary we have 10 digits that we can use to represent any number we like. 0 through to 9. When we count and reach 9, we increment the number to the left of it, and then reset the 9 back to 0.

In binary, we only have two digits to use, 1 and 0. When we reach 1 and want to go further, we need to place an additional 1 before it, and then reset back to 0.