**How To Use An Abacus **

William Gordon John Hope Academy

5515 S. Lowe

Chicago, Illinois 60621

312-962-2760

**Objectives**:

The students will be able to:

1. Demonstrate the properties and operations of a number system

2. Develop an understanding of the commutative, associative and

distributive properties of the mechanics of the abacus

3. To understand the place value of whole numbers using an abacus

**Materials**:

Chinese Abacus (Suan Pan or Soo Pain)

**Strategy**:

A typical Chinese abacus consists of columns of beads. A crossbar separates

the beads. Each column has two beads above the crossbar and five beads below

it. Each upper bead represents five units and each lower bead equals one unit.

The first column on the right is the ones' column; the second column is the

tens' column; the third column is the hundreds'; the fourth column is the

thousands'; and so on. The ones' column represents numbers from one to nine.

Each bead below the crossbar has a value of one (1) and each bead above the

crossbar has a value of five ones (5). The tens' column represents numbers from

10 to 90. Each bead below the crossbar has a value of ten (10). The beads

above the crossbar has a value of fifty (50). The hundreds' column represents

numbers from 100 to 900. Each lower bead equals 1 hundred (100) and each upper

bead equals 5 hundred (500).

To place a number on the abacus, move beads to the crossbar. When beads are

moved away from the crossbar, they are cancelled. This means a lower bead is

cancelled when it is lowered from the crossbar and an upper bead is cancelled

when it is raised from the crossbar.

To place the number 3,684 on the abacus, raise 3 of the lower beads in the

thousands' column. Then lower one upper bead and raise one lower bead in the

hundreds' column to represent 6 hundreds. Next, lower one upper bead and raise

three lower beads in the tens' column to show the 8 tens. Finally, in the

ones' column, raise four lower beads for the 4 ones. Now the abacus shows

3,684.

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