DG went rummaging through our Computer Museum again and came up with this old style Chinese abacus.
This is a 2/5 Chinese abacus, called a “suanpan” 算盘. The 2/5 means that it has 2 beads on the top and 5 beads on the bottom.
The abacus we used in our previous post is a newer, 1/4 Japanese style abacus called a “soroban” (算盤, そろばん, counting tray)
You can use the suanpan the same way that you use the soroban by simply ignoring one top bead and one bottom bead. Just leave ’em aside, like this:
DG: Well that’s stupid. Why have the additional beads if you don’t use them?
Me: With the extra beads, you can do hexadecimal arithmetic.
DG: Hexawhat?
Me: Hexadecimal. A number system based on 16 instead of 10. The extra beads allow you to count up to 15 before you carry over to the next column. Like this:
DG: That’s stupid. Nobody would ever have a reason to do that.
Me: Yes, they would.
DG: No, they wouldn’t.
Me: Yes, they would.
DG: There is no practical application for hexawhat.
Me: Yes, there is.
DG: Prove it.
Me: How many ounces are there in a pound?
DG: Um.
Me: Well….. ?
DG. Um. 16?
Me: Gotcha again.