Real Numbers
Real numbers are rational numbers plus irrational numbers.
Since rational numbers include integers and fractions, then real numbers include:
- integers {..., -5,-4,-3,-2,-1,0,1,2,3,4,5,...}
- fractions (proper, improper, mixed numbers)
- irrational numbers (like , , , etc.)
A set of real numbers, i.e. a group of real numbers, is denoted by .
As we already saw, all these numbers can be placed on a number line, which is called real number line.
Real numbers are called "real", because they are used in math to represent something:
- is used to describe the ratio of circumference of any circle and its diameter
- is used to describe diagonal of unit square
- is used to describe 5 pieces of cake, that is divided into 7 pieces.