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NOTATION AND NUMERATION.
Art. 1. Any single thing, as a peach, a rose, a book, &c., is called a unit, or one ; if another single thing is put with it, the collection is called two; if another still, it is called three ; if another, four; if another, five, &c.
The terms, one, two, three, four, five, &c., by which we designate how many single things or units are under consideration, are the names or expressions of numbers. Hence,
2. Number signifies a unit, or a collection of units.
OBs. Numbers have various properties and relations, and are applied to various computations and practical concerns of life. These properties and applications are formed into a system, called Arithmetic. Hence,
3. ARITHMETIC is the science of numbers.
Numbers are usually denoted by certain letters of the alphabet ; or by arbitrary characters called figures.
QUEST.-1. What is a single thing called ? If another is put with it, what is the collection called? If another, what? What are the terms one, two, three, &c. ? 2. What does number signify? Obs. To what are numbers applied ? 3. What is Arithmetic ? How are numbers usually denoted ?