Real number system

irrational

real but not expressible as the quotient of two integers (cant be written as a fraction)

rational

capable of being expressed as a quotient of integers

real number

any rational or irrational number

integer

any of the natural numbers or zero

natural number

the number 1 and any other number obtained by adding 1 to it repeatedly

Whole number

All positive + 0 (no fractions/decimals) ex. 0,1,2,3,4,5,....