tanishqjain340 wrote this instructable detailing the build of his analog calculator project:
Do simple calculations with your math box.
The next time you need to crunch a couple of numbers, resist the urge to grab a digital calculator. Instead, round up some variable resistors, also known as potentiometers, and wire them into an analog mathematics rig. By twisting the potentiometers’ knobs and measuring the resulting voltage or resistance with a digital multimeter, you can perform simple multiplication and addition without a microprocessor in sight.