HOW TO USE THE ABACUS

PARTS OF THE ABACUS:

THINGS TO REMEMBER:

1) Just like writing numbers, each rod or wire represents a place. Going from right to left, you have the ones place, the tens place, the hundreds place, the thousands place and so on.

2) Beads are counted when they are pushed toward the center bar. To clear the abacus, push all the beads away from the center bar. This is called “zeroing out.”

3) Each bead on the bottom (the “earth beads”) is worth 1 each. In other words, to show “100” you would push up one bead on the hundreds rod. Each bead on top (the “heaven beads”) is worth 5.

4) To move beads, use your thumb to move up earth beads and your index finger to move down heaven beads.

HOW TO ADD WITH THE ABACUS:

1) Show the first number on the abacus.

2) Working left to right, add each digit to the number on the abacus. If there are not enough earth beads on the rod you are working with, use the heaven bead. If there are not enough earth and heaven beads on the rod, use one bead from the next rod.

Example A:
Add 2 + 1. Zero out the abacus. Show the first number by pushing up two beads on the ones rod to the center bar. Then add the second number by pushing up one bead on the ones rod. The answer shown is 3.

Example B:
Add 2 + 4. Push up two beads as above. Since there aren’t enough earth beads left on the ones rod to push up, you will add 5 - 1 instead: take away an earth bead, then push down the heaven bead on the ones rod. The answer shown is 6.

Example C:
Add 2 + 9. Push up two beads as above. Since there aren’t enough earth or heaven beads to make up 9, you will add 10 – 1 instead: take away an earth bead from the ones rod, then push up one earth bead from the next place over (the tens place). The answer shown is 11.

3) Numbers are entered from left to right. Take away from the current rod before adding to the next rod.

Example D:
Add 113 + 248. Zero out. Show the first number by pushing up 1 earth bead on the hundreds rod, 1 on the tens rod and 3 on the ones rod. Now go back to the hundreds rod for the next number. Add the 2 on the hundreds rod by pushing up 2 more earth beads. Then add the 4 on the tens rod by taking away an earth bead and pushing down the heaven bead (1 + 5 – 1). Finally, add the 8 on the ones rod by taking away 2 earth beads, then going to the tens rod and adding 1 earth bead (3 + 10 – 2). The answer shown is 361.

Copyright © 2008 Kathy Ceceri

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