Yes.
No.
Yes.
Yes.
For a set to be closed under any operation, the result of the operation must also be a member of the set. The result of adding fractions is another fraction, thus it is closed under addition. Remember that 8/3, 8/4, 4/4, 2/1 are all fractions - they have a numerator and denominator separated by a line (at an oblique angle on the computer screen). Improper fractions are still fractions.
No.
defference
Yes.
No. Integers are not closed under division because they consist of negative and positive whole numbers. NO FRACTIONS!No.For a set to be closed under an operation, the result of the operation on any members of the set must be a member of the set.When the integer one (1) is divided by the integer four (4) the result is not an integer (1/4 = 0.25) and so not member of the set; thus integers are not closed under division.
Yes, because for any x and y that are positive fractions (y not equal to zero), x/y is also a positive fraction. Note that whole numbers are considered fractions with denominators of 1 -- otherwise it doesn't work.
No. A number cannot be closed under addition: only a set can be closed. The set of rational numbers is closed under addition.
The set of even numbers is closed under addition, the set of odd numbers is not.
The product is the answer to a multiplicationproblem.