What sets are closed under division?

Answer 1

For example:* The set of real numbers, excluding zero

* The set of rational numbers, excluding zero

* The set of complex numbers, excluding zero

You can also come up with other sets, for example:

* The set {1}

* The set of all powers of 2, with an integer exponent, so {... 1/8, 1/4, 1/2, 1, 2, 4, 8, 16, ...}

Answer 2

The set of rational numbers or the set of real numbers, in both cases excluding 0, are closed under division.