Yes.
The numbers are not closed under addition because whole numbers, even integers, and natural numbers are closed.
l think multiplication
The set of positive whole numbers is not closed under subtraction! In order for a set of numbers to be closed under some operation would mean that if you take any two elements of that set and use the operation the resulting "answer" would also be in the original set.26 is a positive whole number.40 is a positive whole number.However 26-40 = -14 which is clearly not a positive whole number. So positive whole numbers are not closed under subtraction.
Integers are closed under division I think o.o. It's either counting numbers, integers or whole numbers . I cant remember :/
If you can never, by multiplying two whole numbers, get anything but another whole number back as your answer, then, YES, the set of whole numbers must be closed under multiplication.
Yes.
Yes.
The numbers are not closed under addition because whole numbers, even integers, and natural numbers are closed.
l think multiplication
If you mean the set of non-negative integers ("whole numbers" is a bit ambiguous in this sense), it is closed under addition and multiplication. If you mean "integers", the set is closed under addition, subtraction, multiplication.
no
They form a closed set under addition, subtraction or multiplication.
Because if X and Y are any two whole number, then X*Y is also a whole number. Always.
Yes. That means that the product of two whole numbers is defined, and that it is again a whole number.
No. Since -1 x -31 (= 31) would not be in the set.
The whole numbers are not closed under division! The statement is false since, for example, 2/3 is not a whole number.