Why use an abacus?
The abacus is highly prized in areas of the world that don’t have steady electricity. Many, many people can compute on it faster than you could use a calculator. It’s also a fine tool for the visually impaired. As an arithmetic teaching tool, it has been of immense value. In fact, Forbes.com—20 most important tools ranks the abacus as the second most important tool of all time. (The first is the knife.) The wikipedia entry has a few tutorial links, and I’m sure the web in general has a lot of them. The one I liked best is from Totton Heffelfinger and Gary Flom—Abacus: Mystery of the Bead. From their tutorial– Dividing the upper and lower portion of the soroban is a horizontal bar called a beam or reckoning bar. On a modern-day soroban, 1 bead sits above the beam and 4 beads sit below. (The Chinese use 2 beads above and 5 below.) The beads above the beam are often called heaven beads and each has a value of 5. The beads below are often called earth beads and each has a value of 1. The v
