Anyone else remember these - they came out about 1955 and cost about $1. I had one but didn’t put it to too much use IIRC.
https://www.google.com/search?q=magic+brain+calculator&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari
https://www.google.com/search?q=magic+brain+calculator&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari