Abacus

The Abacus

The abacus is an ancient calculator. The Chinese used it around 500 B.C.

You can preform addition, subtraction, and multipacation on it. In about 1600 A.D. the Japanese started to use this ancient calculator. Some scientist found parts of a abacus possibly used by the ancient Aztec. The abacus consists of two sections. An upper and a lower part. In the inside of the upper and lower parts are eight bars. On the upper part of the abacus, there are two beads on each bar. Those beads have the value of five. On the lower part of the abacus, there are five beads on each bar. Those beads have the value of one. Some people refer to the abacus as the 2/5 abacus. The 2/5 abacus lasted until about 1850 A.D.

Adding on the Abacus

When adding on the abacus you start with zero. To get to zero you would put all the upper beads up, and all the lower beads down. By moving the upper beads down to the amount you need, and the lower beads up to the amount you need you can add.

Subtraction on the Abacus

Subtartion is about the same as adding except you start with the number you need to subtract from. Then take away the amount that you need. The remaining beads will be your answer.

Other Subjects that can use the Abacus

The abacus can be used in just about any subject. In science it could be used for many things. For example, calculating experiments. In social studies you could use it for figuring out how many years ago a group of people existed. In reading it could be used for finding out how many pages you read the whole year.

I think that the abacus is a good way to add, subtract, and multiply. I think that it was well thought through when it was invented.

Sources:

http://www.ee.ryerson.ca:8080/`elf/abacus/