This is one of those things that will, most likely, make you kick yourself. I accept no responsibility for any bruised ankles etc.....

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The answer to the problem is "2"

The reason - ignore the numbers - that is, the actual numerical values - imagine they're just shapes..... Then count the closed loops (or elipses) - for example a 0 is a closed loop - an 8 has 2 closed loops - 6 and 9 have one each. Add the total number of closed loops in each set of numbers and you'll come up with the answers listed.

I did notice (as have other people by PM) that there are no number 4's anywhere - I imagine this is to reduce the possibility of confusion of ambiguity as it kinda contains a closed shape, albeit a triangle as opposed to a loop......