Thursday, February 23, 2012

Inequalities and Number Sets

It is important to know the sets N, Z and R and how to graph these on the number line.

On page 23 of the Maths tables the sets of numbers that you need to know are listed - however it is easier to learn them here. When written in this order each set includes the numbers in the previous set.

Natural Numbers - Symbol N = {1, 2, 3, 4, ... }, whole positive numbers.

Integer Numbers - Symbol Z = { ... 3, 2, 1, 0123 ...}, whole positive and negative numbers (and zero)

Rational Numbers - Symbol Q = any number that can be written as a fraction using two integers, but you cannot have zero as the denominator because it is impossible to divide by zero. You will only be asked to show the sets N, Z and R on the number line. The set Q is used when you are asked to write your answer as a fraction.

Real Numbers - Symbol R = all the numbers on the number line.  This includes the rational numbers and the irrational numbers (numbers that cannot be written as fractions e.g. pi, √2 etc. 




An open or empty circle is placed around the 2 because 2 is not included. For less than or equal use a full or coloured in circle.


This video explains what rational and irrational numbers are.





0 comments: