#34: Pocket Adder
This next device came around way before the days of pocket calculators, let alone iPhones that can calculate long equations in a fraction of a second. If you went to the store and wanted to work out the price of something, it was essential for you to have one of these. It’s easy to forget how complicated things were back in the day, now that we have everything we need in the palm of our hands.
They’d ensure that you got the price of the products exactly right – just as long as you pressed the buttons correctly! Whenever we used one of these things, we’d always get nervous about not pressing it properly. If you needed to do subtraction, you were out of luck, as there was a separate device for that.