Casio's touch screen calculator watch is almost as old as me

The AT-552 Janus watches by Casio were released in 1984 and support touch screen gestures to allow you to use the inbuilt calculator.

They're not cheap, a minimum of £233 on eBay for a pre-owned one and around £500+ for a 'new' one.

We have a calculator in our pockets at all times now so there's unlikely to be much appeal for this type of functionality but from the demo in the video it looks accurate and it's pretty stylish.