The Natural Numbers
The natural numbers are the numbers that we use to count. The set of natural numbers is usually denoted by the symbol .
The natural numbers are often represented as equally spaced points on a number line, as shown in the figure, increasing forever in the direction of the arrow.
The sum or product of two natural numbers is also a natural number. For example,
Sum:
Product:
This is not always true with differences or quotients of natural numbers. For example, is a natural number, but is not. That is, when we subtract a larger natural number from a smaller natural number, we do not get a natural number.
Similarly, is a natural number but is not. When we divide natural numbers that do not divide evenly, we do not get a natural number.
The set of natural numbers and zero is called the whole numbers . The set of whole numbers is usually denoted by the symbol .
The whole numbers are often represented as equally spaced points on a number line , as shown in the figure, increasing forever in the direction of the arrow
The sum or product of two whole numbers is also a whole number, but the difference or quotient of two whole numbers is not always a whole number.