How do I do this?

Yep, you have the same amount of space as the previous problems so it would be better to do so. Makes it look complete since a question without an answer may seem odd.

13. You can insert a number for ? to create your own problem such as 1/8 of 16 or 2/8 of 16 or 3/8 of 16.

If it was 1/8 of 16, then you know that every 1 out of 8 boxes would be selected meaning that you get 2.

Do I solve the problem?

Yep, create your own problem and solve it, too.

So that means that I have to draw them too?

Alright, thank you!