246 because all other have atleast 2 odd digits
Irrational numbers.
None. There is nobody to whom triangular numbers belong.
Rational numbers.
mixed numbers
No, they can belong to infinitely many subsets.
The set of numbers which 3 does not belong is the set of even numbers.
10 belongs to the set "natural numbers", but it can also belong to whole numbers, and rational numbers
Rational numbers
Counting numbers
Irrational numbers.
odd numbers, perfect square numbers
None. There is nobody to whom triangular numbers belong.
rational and prime numbers
Rational and Real numbers
Rational numbers.
mixed numbers
No, they can belong to infinitely many subsets.