The set of numbers which 3 does not belong is the set of even numbers.
Natural (counting) numbers; integers; rational numbers; real numbers; complex numbers. And any other set that you choose to define, that happens to include the number 7 - for example, the set of odd numbers, the set of prime numbers, the set of the numbers {5, 7, 14, 48}, etc.
10 belongs to the set "natural numbers", but it can also belong to whole numbers, and rational numbers
A set is just a way of describing numbers, and numbers can be described in more than one way. If set A is (for example) all positive prime numbers, and set B is all numbers between 0 and 10, then there are some numbers (2, 3, 5, and 7) that could belong to both sets.
The set of even numbers
The set of numbers which 3 does not belong is the set of even numbers.
Natural (counting) numbers; integers; rational numbers; real numbers; complex numbers. And any other set that you choose to define, that happens to include the number 7 - for example, the set of odd numbers, the set of prime numbers, the set of the numbers {5, 7, 14, 48}, etc.
10 belongs to the set "natural numbers", but it can also belong to whole numbers, and rational numbers
It belongs to the rational numbers which is a subset of the real numbers. The reals, in turn, is a subset of complex numbers.
A set is just a way of describing numbers, and numbers can be described in more than one way. If set A is (for example) all positive prime numbers, and set B is all numbers between 0 and 10, then there are some numbers (2, 3, 5, and 7) that could belong to both sets.
Counting numbers
Irrational numbers.
Any set of numbers that contain them! For example, they belong to the set {10, 11} or {10, 11, sqrt(2), pi, -3/7}, or {10, 11, bananas, France, cold} or all whole numbers between 3 and 53, or counting numbers, or integers, or rational numbers, or real numbers, or complex numbers, etc.
The set of even numbers
Infinitely many sets: they belong to the set {0, 2, 4, 5, 7, 9}, and to {0, 2, 4, 5, 7, 9, 92} and {0, 2, 3, 4, 5, 7, 9} and {0, 2, 4, 5, 5.35, 7, 9} and {0, 2, 4, 5, 7, sqrt(53), 9} and N0, the set of Natural number including 0, Z, the set of integers, Q, the set of rational numbers, R, the set of real numbers, C, the set of complex numbers as well as any superset of these sets.
It belongs to the set of prime numbers
Rational and Real numbers