Here’s another one of my favourite maths objects: the Correntator. It’s a simple mechanical tool to add up amounts of money. I bought it for about a tenner (new money) at a market.
This video is extremely shonky. Blame my phone, which can’t bring itself to record for more than 250 seconds at a time.
More information about the Correntator.
Somewhere I have the pointer to your correntator