Question 1064462: Which operations is the following set closed under: {... , -3, -1, 1, 3, ...}?
Answer by Edwin McCravy(20059)   (Show Source):
You can put this solution on YOUR website! {... , -3, -1, 1, 3, ...}
That's the set of all odd integers.
Since an odd integer times an odd integer is an odd integer,
The set is closed under multiplication (but not addition, subtraction,
or division)
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Of course there are some other contrived operations for which it is
closed, such as the "heart operation" ♥, "raising to the
absolute value of a power" defined by
x ♥ y = x|y|
Edwin
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