I started working in my Dad's office when I was 14. Luckily, it was mostly "seasonal", but every Sat & Sun in tax season, my Mom or I would check all the tax returns my Dad prepared before they were issued. We worked 9am to 9pm both days. No computers back then, it was a big deal that he had electric adding machines (instead of the old ones with that hand crank you pulled down). The top of the ribbon was black, the bottom red (for negative #s).
And for photo copy, you sandwiched the original between two different papers, exposed it to the light, then removed the original and ran it through a solution that produced the image. If you forgot to remove the original before you ran it through the solution, you lost it, no way to recover it!
It was a good hands on way to learn taxes! Every year, I bought a gun or bow with the extra money I earned during tax season.
But my favorite thing to do every year was in the better weather, when we went up to my Aunt & Uncle's farm and helped with the haying. We did not go up there in the winter, they were in the snow belt, and my cousins would tell me how the snow drifted against the house so bad they had to go out the upstairs window!