What is an abacus? Definition and Chinese Abacus

An abacus is an ancient tool or device that is stilled used today in some countries such as in Japan and China. 

The abacus can be used to do some basic math such as adding, subtracting and even multiplication. It is commonly used in the United States to help students understand place value. 

How to use an abacus

First, here are a few things to keep in mind!

• The red and green shapes are called beads.

• The red beads are in the lower deck and the green beads are in the upper deck

• The numbers increase in value as you move from right to left. The set immediately on the right is 10 times the set on the left.

Lower deck with 5 beads

Starting from the right side and moving to the left, each of the red beads in the first set is equal to 1. 

Each of the red beads in the second set is equal to 10

Each of the red beads in the third set is equal to 100

Each of the red beads in the fourth set is equal to 1000

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All the way to the last set on the left where each of the red beads is equal to 100,000,000

Upper deck with 2 beads

Starting from the right side and moving to the left, each of the green beads in the first set is equal to 5. 

Each of the green beads in the second set is equal to 50

Each of the green beads in the third set is equal to 500

Each of the green beads in the fourth set is equal to 5000

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All the way to the last set on the left where each of the green beads is equal to 500,000,000

Below, see how to use the abacus to show 26,408