**Types of Numbers Explained**

Mathematicians use several types of numbers..

Integers - These are the "whole numbers" {..-3,-2,-1,0,1,2,3..}

Rational Numbers - These are "fractions" a/b where a and b are integers.

Irrational numbers - These are numbers which are not integers and not rational numbers.

The set of all Integers, rational numbers and irrational numbers is known as the Real Numbers and are denoted by R.

Complex numbers - These are built using the imaginary number i (defined by i^2=-1) like this..

complex number=a+i*b where a and b are Real Numbers.

The set of all complex numbers is denoted by C.

It's the single number i that makes complex numbers possible. The part a of the complex number is called the real part, while b is called the imaginary part. We can plot complex numbers as points (x,y) in 2D by plotting a on the x axis and b on the y axis, and this 2D space is called the complex plane. Notice that the x axis of the complex plane is R.

So R is a subset of C, it's just the complex numbers that have b=0.

That's the number jargon!

I've not included the transfinite numbers invented by Georg Cantor. Those things are amazing!

Content written and posted by Ken Abbott abbottsystems@gmail.com