A real number is either rational or irrational. A number is
rational if it can be expressed in the form of x / y where x and y
are both integers.
Example
4/5 is rational since 4 and 5 are both integers
7 is rational number since it can be expressed as 7/1 and 7
and 1 are both integers
2.4 is rational since it can be expressed as 12/5 and both 12
and 5 are integers
Rational numbers either have a terminating decimal such as 6.254
or a repeating decimal such as 0.3333333
Irrational numbers on the other hand can not be expressed
in the form x / y, and have a never ending and never repeating
decimal. For example pie is an irrational number.
Other types of real numbers include prime numbers. Prime
numbers are a positive integer which has exactly two factors, 1
and itself. The first 4 prime numbers are 2, 3, 5, and 7.
All other positive integers are composite and they have 3 or more
factors. For example 12 has factors 1, 2, 3, 4, 6, 12 . Note that
the number one is neither prime nor composite since it has exactly
one factor. |
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