Theories about chalkboard multiplication circle from 1917?
This was a fun discovery and I wonder if families have any theories about the way the numbers are ordered around the circle. :) NPR article on discovered chalkboards
My guess is that the teacher was providing random practice, similar to this game I posted at my blog. Students would pick a times table and go around the circle, pointing to each number and saying either the product only or the whole equation ("N times factor = product").
