So, this is two-pi right over there. For example, if you had - -2 , you can think of it as the opposite of -2.

## Real Number System

Putting these two ideas together we get: So this circle, over here, this represents all of the numbers that can be represented as the fraction of two integers, and, of course, the denominator can't be equal to zero, because we don't know what it means to put a zero in the denominator. The integer in the denominator is 1 in that case. These two things are actually the same number, just different ways of representing them.

Classify numbers: And if something cannot be represented as a fraction of two integers, we call irrational numbers. After completing this tutorial, you should be able to: Actually it is 3.

Share on Facebook. In fact, there are no elements in N that are in I. The set of real numbers is made by combining the set of rational numbers and the set of irrational numbers.

## Integers and rational numbers

It is shown with the symbol. So, these are integers, right over here.

Also, 3. All rational numbers are real numbers, so this number is rational and real. Of course, numbers are very important in math.

This is the ratio of two integers. Well, this, for sure, can be represented as a fraction. Distance is always going to be positive unless it is 0 whether the number you are taking the absolute value of is positive or negative.

And the size of these circles don't show how large these sets are. Similarly, 5 is not a perfect cube. The natural numbers and the whole numbers are both subsets of integers. So, three is a whole number, it's an integer, and it's a rational number.