Just for fun, I was thinking of buying an abacus. Dhould I get a 4:1 abacus or 5:2 abacus? Any abacus geeks here able to weigh in?
5:2 abaci work perfectly well for base 10. On the other hand, 4:1 abaci don't really work at all for anything above base 10, so the 5:2 abacus will give you more flexibility.
If you really want to use base 16, get a 4:1. All the 5:2 abacus are too large and old formatted. Slow to use.
Get the squiggly ones in the doctor's office lol.