Doing basic calculations on your home computer just got a lot simpler, thanks to this week's Web SpotSite: e-abacus.com, which fulfills its promise to be “The Place Where Mathematics Is Arithmetic Again.” The site consists of just one screen presenting the image of an ancient abacus—a rustic-looking wooden frame strung with 10 parallel wires, each wire strung with nine beads. The site is operated by the simple point-click-drag of a mouse, which is used to move the multicolored beads from one side of the frame to the other. Moving these beads to add, subtract, multiply or divide on the virtual abacus is also very easy—which pretty much goes without saying. The original abacus was used by Egyptians as far back as 500 B.C. before moving through the ancient cultures of Europe and China. How hard could it be? Basically, each bead on a given wire has the same value: either 10 or some multiple or submultiple of 10. For example, all of the beads on a particular wire may have a value of 1, making this the units wire, or 10, making this wire the tens wire. Numbers are represented and added on the abacus by grouping beads together. To represent 155, for example, five beads on the units wire are separated from the others on that wire, five beads on the tens wire, and one bead on the hundreds wire. To add 243 to 155, three more beads on the units wire are slid over to join the group of five, four more beads on the tens wire join the five there, and two more beads on the hundreds wire join the one there. The number 399 is now represented on the abacus . . . which . . . is . . . not right! The answer should be 398. Shouldn't it? Let's see: 3 plus 5 is 8, 4 plus 5 is 9, and 2 plus 1 is 3 . . . so . . . yeah, it's 398, unless the cursor moved too many beads.
