1. History of Abacus By: Huy Do & Trinh Huynh By: Huy Do & Trinh Huynh

2. Outline History of abacus History of abacus Abacus lingo Abacus lingo Why use abacus Why use abacus How to add How to add How to subtract How to subtract How to multiply How to multiply How to divide How to divide

3. History of Abacus Abacus ? (personal calculator) Abacus ? (personal calculator) - a device used for “+”, “-”, “x”, “/” - a device used for “+”, “-”, “x”, “/” - does not require the use of pen & paper and good for any base number system - derives from the Greek word ABAX – table or board covered with dust Most historians believe the abacus was first created in Central Asia Most historians believe the abacus was first created in Central Asia From there it spreads West to Europe, and East to China, and its neighboring Oriental countries From there it spreads West to Europe, and East to China, and its neighboring Oriental countries “Modern” Chinese abacus “Modern” Chinese abacus - appeared in China between the 12 th and 13 th century AD.

4. “Modern” Chinese abacus lingo 12345678910111213

5. Why use Abacus? Run by hand Run by hand Simple to use Simple to use Operate for years Operate for years Teach you how to manipulate numbers Teach you how to manipulate numbers - how each digit relates to the others and use that knowledge to do all the major operations - +,*,/ - how each digit relates to the others and use that knowledge to do all the major operations - +,*,/ Let you learn all about the base ten system Let you learn all about the base ten system Show you how to math in the decimal system and the binary system Show you how to math in the decimal system and the binary system Can solve problems just as fast or even faster than a modern electric computer. Can solve problems just as fast or even faster than a modern electric computer.

6. How does it work? The first column is for units The first column is for units The second column is for tens The second column is for tens The third column is for hundreds The third column is for hundreds And so on… And so on…

7. How to Add 8 + 5

8. How to Subtract 13 - 9

9. How to Multiply 6 x 4 Feed 6 beads into abacus 4 times

10. How to divide 24 / 8 How many 8’s are there in 24