Adders belong to the group of arithmetic logic units. Other arithmetic logic units, such as comparators, compare binary numbers. However a digital adder adds binary numbers.

Among the class of adders also other logic units are listed,
those that **subtract**, **multiply** or
**divide** two numbers.
Because in essence,
the four **basic arithmetic operations** can all be replaced
by the adding operation.

However, there are a **wide variety** of adders.
Because you can build adder working with **whole numbers**,
**negative numbers** or ever more complicated systems.
Moreover, it is for all adder of **very large binary numbers**
a challenge to produce
the result as **quickly as possible**.

In this **first part** you learn how to set up
the different adders, subtractors, etc..
In **16 experiments** you build adders from **logic gates**.
Thereby you improve gradually your adder.

In the **second part** (Go on...)
you are working in another **6 experiments**
with pre-programmed adder IC's.

Let's go...and have fun...