ok
so we first got natural number or counting numbers
this is like 1,2,3,4 etc
then whole numbers, that is natural numbers plus 0
so 0,1,2,3,4, etc
then integers, that is whole numbers plus negatives
so -4,-3,-2,-1,0,1,2,3,4 etc
then rational numbers, these are numbers that can be written in form a/b where a and b are integers and b≠0
so like -4/1 or 1/2 or something like that
then irrational numbers, these can't be written in a/b form, they have to have a symbol or an unsimplified square root
exmaples, π, √2
these are the sets that make up real numbers
note: an irrational number times a rational number results in an irrational number
so
√42=(√2)(√3)(√7)
√2 is irrational so √42 is irrational
it belongs to the irrational numbers subset
