Tutorials 2+3 Addition and Subtraction

In the second and third tutorial we explore how a computer adds and subtracts binary numbers. Adding sits at the heart of most if not all computations - algorithms cleverly decompose higher mathematics into addition. Subtraction is achieved by forming the binary complement of the subtrahend and then adding it. Multiplication, is a sequence of additions. Division is a sequence of subtractions.

The Blueberry4 Adder and Inverter modules form, what we call, the computer's Arithmetic Logical Unit.

Addition:

Subtraction: