Different Types of Numbers

Date: 4/13/96 at 21:36:37
From: Anonymous
Subject: Reals, intergers, whatever...

I don't understand how to tell the difference between the 
different kinds of numbers. i.e. reals, integers, and stuff, and I 
was hoping you could help me. 

Date: 4/14/96 at 1:21:51
From: Doctor John
Subject: Re: Reals, integers, whatever...

Whole numbers are the numbers you use when you count:  0,1,2,3,...

Integers are all of the whole numbers and their negatives.  They
are ...-3,-2,-1,0,1,2,3,...  (The three dots means you keep going 
in both directions.)

There are also rational numbers.  Rational numbers are all the 
different kinds of fractions.  1/2, 3/4, -2/3, and 5 are all 
rational numbers.  Irrational numbers are numbers which you can 
write as decimals but not as fractions.  Pi and the square root of 
2 are irrational numbers.

Real numbers are all of the rational and all of the irrational 
numbers put together.  All of the numbers you normally deal with 
are real numbers.  (There are also other kinds of numbers called 
imaginary numbers, but don't worry about those right now.)

-Doctor John,  The Math Forum