Now that we have covered rational numbers and irrational numbers let us see how far we have come in learning numbers.
First we learnt about Whole numbers from 0 to 10, 11 to 20 and 21 to 100 and so on till over a million. These are countable whole numbers in that they represent whole quantities.
Then we learnt about fractions which were numbers that were not ‘whole’, instead they were numbers in between, like halves, quarters and fractions with any general whole numbers in the numerator and denominator.
We learnt how to convert these fractions into decimals which are essentially another representation of these fraction numbers.
We must also keep in mind that these numbers usually have a counterpart in the negative side as negative integers and negative fractions and negative decimals.
In today’s lesson we learnt how to generalize integers, fractions and decimals into the set of rational numbers.
We also learnt about a new set of numbers called irrational numbers including square roots and the constant pi.
Imagine the entire collection of these numbers. That is to say, rational numbers AND irrational numbers. This entire set makes up for all the numbers we see around in the world in ‘real’, quantifiable, physical forms. They are REAL NUMBERS.
This collection of Real Numbers is sometimes represented as a line with points on the line standing for the numbers. Pick any point on the line and it will correspond to a real number. Conversely, pick any real number you can think of and it will have a point representation on this line.
This line is called the Number Line.