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, depending ...

Most of us can do simple math in our heads, but some people just can’t seem to add two numbers between 0 and 3 without using paper, like [Aliaksei Zholner] does with his fluidic adder circuit built ...