Let us revise each set
The whole number set is the set of all positive integers with zero
Natural number set is the set of all positive integers
The integer set is the set of all positive, negative, and zero of whole numbers
A rational number set is the set of integers, fractions, decimals, and repeating decimals any number can be written in the form of a/b where b is not equal to zero
It is a repeated decimal number and belongs to the set of the rational numbers
Irrational number set is the set of the number that can not be in the form of a/b
as the approximated numbers like pi, roots of the numbers
Set of the real numbers contains all the above numbers
Since 4.03 is a repeating decimal, then
It is a rational number, then
4.03 belongs to the set of the rational numbers
The smallest circle is a set of natural numbers
When adding zero to it we will have the whole numbers
Whole numbers + negative integers = set of integers
Integers + fractions, decimal, and repeating decimal = Rational
Rational + irrational = Real