I found the following puzzle in a kindergarten book:
Can anyone give a clear explanation as to what the answer is and why?
The first time I tried to solve it I got an answer of 6, by noting that the sum of the top and bottom pair of each set are equal:
For the first:
3 6 7 4 5
3+6 = 4+5
2 9 9 8 3
2+9 = 8+3
And so on.
But this solution completely ignores the centre number, leading me to believe it is wrong! Can anyone think of a better or more logical solution?