## 4.2 Outline

- Hindu-Arabic numerals
- decimal numeration system
- algorists vs. abacists

- Decimal system – grouping by tens
- Expanded notation
- meaning of a number
- decimal point

## 4.2 Essential Ideas

The Hindu-Arabic or decimal numeration system is the one we use everyday. Its properties include:

- It uses ten symbols, called digits.
- Larger numbers are expressed in terms of powers of 10.
- It is positional.

The essential idea of this section is expanded notation.