A real abacus has beads in sets of 5 and 2.
You push 5 up, then you pull them all down and 1 of the top ones.
The top ones equal 5 units.
They are so much easier to read. Your brain can instantly pick out 1-5. It is not good at 7-8-9 objects.

Invest in food! It is currently paying 12% interest every year. And will probably pay more in the future! And you can eat it. (people always complain about not being able to eat gold)