1. Natural numbers are counting numbers starting from 1, i.e., 1, 2, 3, 4,...
2. Whole numbers are counting numbers including zero, i.e., 0, 1, 2, 3, 4,...
3. Integers are whole numbers including the negative of natural numbers, i.e., ...−3, −2, −1, 0, 1, 2, 3,...
4. Rational numbers are all the integers including the fractions between integers, i.e., 12, −32, 0, 1, 2, 56,...
5. Real numbers include all of the above mentioned numbers and irrational numbers.
So, the correct order is:
1 < 2 < 3 < 4 < 5