Back in the 60's before the change to decimal in the UK, and WAY before computers, I used to run 2 bank sub branches. I had to enter every transaction on a huge piece of paper, then get it to balance with the cash in the till once I'd got the door closed at midday. This was very difficult at one branch as the whole village used to pay in their ill gotten gains - they were all selling stuff from catalogues to each other! It's the inbreeding you know.

If I hadn't balanced everything, I had to figure it all out on the bus going back to the main branch, as English kids of 19 didn't generally run cars in those days.

Working in a bank in those days didn't half improve your mental arithmetic - not to mention your muscles - the old coinage was much heavier than the decimal stuff. As I found when I dropped a gigantic cloth bag of old pennies on the bandit alarm trigger under the till....