## Numbers

Students of mathematics have created many different names for the wide variety of numbers that they have found or have invented. Here is a partial listing:

Natural Numbers -- Most people think of 1, 2, 3, 4, 5, 6, ...

Integers -- These can be positive or negative numbers, like ..., -4, -3, -2, -1, 0, , 2, 3, 4, 5, ...

Rational Numbers (a ratio of two integers, usually called fractions), like 3/4 or -22/7 or 8/1

Irrational Numbers are numbers which cannot be written as a ratio of two integers.

Complex Numbers can occur, for example, when we try to find the square root of a negative number, like

Natural Numbers -- Most people think of 1, 2, 3, 4, 5, 6, ...

Integers -- These can be positive or negative numbers, like ..., -4, -3, -2, -1, 0, , 2, 3, 4, 5, ...

Rational Numbers (a ratio of two integers, usually called fractions), like 3/4 or -22/7 or 8/1

Irrational Numbers are numbers which cannot be written as a ratio of two integers.

Complex Numbers can occur, for example, when we try to find the square root of a negative number, like