Puzzle, not sure where to post this.

Ditto with pka. I can make all of those answers work. Where did you get this from? If we know the source we might be able to give you a hint as to how to proceed.

-Dan
 
There is no context to it, just the image and the possibilities. Question says find the missing number
 
There is no context to it, just the image and the possibilities. Question says find the missing number
The kind of context from which we could learn something would be if it is in a set of similar problems in which we can see what kind of patterns they have in mind. Are there others we could compare this to? Or is it part of a lesson about some particular aspect of arithmetic? If it's just a lone puzzle, then all you can do is guess and check.

This sort of puzzle has a correct answer only in the sense that, once you guess it, you get a feeling that this must be what they were thinking. It is not really mathematics; you can't prove any one answer is the only one that could make sense. The layout of the numbers may suggest possibilities to try (e.g. combine numbers connected by a horizontal line first), but has no meaning in itself.
 
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