This 2-bit adder was a lot of work to build. It uses a total of thirty-six 555 timers and it does have the option of adding or subtracting numbers. It’s a rather unorthodox use of the part ...

The Adder/Subtracter module can implement adders (A+B), subtracters (A–B), and dynamically configurable ... The Beyond BA22 32-bit processor offers the highest code density of any processor in its ...