Answer
whole numbers
Work Step by Step
The set of natural numbers is { 1, 2, 3, 4, 5, ... } .
The set of whole numbers is { 0, 1, 2, 3, 4, 5, ... }
The set of integers is {... , -4, -3, -2, -1,0, 1, 2, 3, 4,...}
The set of rational numbers$: \displaystyle \frac{a}{b},\ b\neq 0$, and b integers
Irrational numbers: are not rational (can not be written as $\displaystyle \frac{a}{b},\ b\neq 0$)
Real numbers: all rational and irrational numbers.
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A person can have no siblings, so 0 is in the set.
If the person has siblings, we can count them. The set used for counting is the set of natural numbers,
So, we have zero and the natural numbers... which is the set of
whole numbers.
