Agree. I taught myself in order to teach a young relative, and it really improved my ability to handle mental calculations at the simple end of the mathematical

Agree. I taught myself in order to teach a young relative, and it really improved my ability to handle mental calculations at the simple end of the mathematical operational spectrum. What was really weird was doing the abacus work, moving beads, all in chunks of 5 or 10, and then looking at the final results without any preconceived notion of what the results were. Totally fresh eyes as I counted the final set of beads. The manual movement was one thing, but the motion didn't cause me to visualize "numbers" as I understand them. Completely separate pathway to the same answer.