|
Please, support our project in social networks: |
Abacus, how to use an abacusAn abacus is a frame of beads on wires, used for counting and for simple mathematical calculations. Its principle was known to the ancient Assyrians, and early Greeks and Romans used the bead-frame abacus. Today in Western countries it is used as a toy or to teach counting to young children. But in some countries it is still used in shops, offices. Even in banks in this countries by abacus planning some operation. The Chinese call it suan pan and the Japanese soroban.
Abacus, how to use an abacus for kidsAn abacus is a good way to teach your kids basic subtraction and math. For example, abacus at picture above has nine columns of beads. Beads above the crossbar, when lowered, denote fives -from right to left, five units, five tens, five hundreds and so on. Beads below when raised, denote one unit, one ten, one hundred, in the same way. Picture (A) is set for 2500. To add a further 2500 we raise two more beads in the thousands column and lower one bead in the hundreds column (picture B). Since the two fives in the hundreds columns equal one unit in the thousands column, and five lower beads (4+ 1) in the thousands column equal one upper bead, we cancel the beads in the hundreds and thousands columns in Picture (B) and lower one five-unit bead in the thousands column. Picture (C) shows the correct way of representing the total (5000). You can read these articles also: |
||||||||||||
|
|
|||||||||||||
|
|||||||||||||
|
Wikipedy.com @ - Online Encyclopedia |
|||||||||||||
