How to Use "abacus" with Example Sentences

1. In english we call it an abacus .
2. The chinese invented the abacus ; india invented the binary and the decimal systems .
3. When students mastered the abacus , they developed more confidence in their ability to do math .
4. China , which invented the abacus as we know it today , should tell its statisticians to fix theirs .
5. Such fine calibrations may date back to the use of the abacus , and to an old chinese convention that assumes a 360-day year for the purpose of reckoning interest payments .