We learned about the abacus, and it was offered as an option during tests; but most folks didn’t understand it. I used it quite a bit, and I can still do math in my head while visualizing those little disks/beads.
Most kids, and probably a large number of their teachers today don't even know what one is. The only thing that technology has done for people, is to offer them the opportunity to be lazy, and plenty have chosen that option.