Question

Which operations is the following set closed under: {2, 4, 6, ...}? The answer has to be written out and there are no choices

Answer 1

Its closed under addition and multiplication 

Answer 2

The set is taking the previous term and adding two to it to get the next term.
So: 2 + 2 = 4, 4 + 2 = 6, and so on.
The next three terms are 8, 10, and 12.

Hope this helps!