Problema Solution

the set of odd integers is closed under the operation of

Answer provided by our tutors

If you add 1 + 3 you get a non-odd number, so Addition is not closed.

If you subtract 3 - 1 you get a non-odd number, so subtraction is not closed.

If you multiply two odd numbers, you always get an odd number, so multiplication is indeed closed.

If you divide 7 into 5 you get something that isn't an odd number, so it is not closed.

So only muliplication is closed.