sets

SETS OF NUMBERS & THEIR PROPERTIES






SETS OF NUMBERS

The sets that we will be concentrating on for the rest of this web site are sets of numbers.
Below you will graphically see the most common sets of numbers, along with brief descriptions of each major set.

Whole numbers are positive counting numbers.
Whole numbers do not have any decimals and
they cannot be fractions.
The whole numbers are {0,1,2,3,4,5,...}
Integers are the positive and negative counting numbers.
Integers do not contain decimals and
they cannot be fractions
{Whole numbers} Ì {Integers}
The Integers are
{...-5,-4,-3,-2,-1,0,1,2,3,4,5,...}
Rational numbers are any number that can be expressed as a ratio of two integers (a ratio being one number placed over another with a "/" in between-we will examine this more thoroughly in the unit on fractions)
{integers} Ì {Rational numbers}
The Rational numbers include decimals, and fractions.
Just as an example of some Rational numbers, {1/3, 5/1 (=5), -2/3, -2/1 (=-2), 0.56, -0.02} Ì {Rational numbers}
The Irrational numbers are any number that cannot be expressed as a ratio of two integers
The greek constant pi, (p) which is used in calculating the area and curcumference of a circle, is one example of an Irrational number. p is approximately equal to 3.14
When you come to square roots later in this tutorial, you'll see other Irrational numbers
The Real numbers encompass everything
{Real numbers}={Rational numbers} È {Irrational numbers}.




PROPERTIES OF THE REAL NUMBERS

Okay we arrived at the Real numbers? So what?
The Real numbers have some very important properties which I'll explore just for a moment.
I know this isn't the most exciting subject but believe it or not these properties are how subjects like algebra work. Just drink a cup of coffee to stay awake, and it will be over in a minute




You now have reached the end of the Set unit
Now you have a few options
You could review what you learned about sets with a little test,
You could go back to the Set main page to review a lesson,
You can go back to the main page to choose your next lesson, or
Go on to the Whole number unit.