And today, in class, I had a lot of great help from students as we did some primitive counting -- in "both directions". That is, we could take one of our counting numbers, e.g. 97, and show how we'd write that on our tally stick; but also we examined what would be happening on the King's end, in the counting house. There, they'd take a tally stick and convert it back to a number of sheep, and then calculate the taxes.