Each can be a classification within another group of numbers.
For example:
All whole numbers can be natural numbers (but not the other way around)
All natural numbers and all whole numbers can be integers (also not the other way around)
All natural numbers, whole number and integers can be rational (not the other way around :):):)):))
Natural numbers: 1, 2, 3, 4...
Whole numbers: 0, 1, 2, 3...
Integers: -2, -1, 0, 1, 2...
Rational number: -2.5, -1.72, 0, 1, 3.77... (any number that can be written down)
