Another puzzle following up the overwhelming clamour for the last one
This is the Magic square puzzle - Level 8, so definitely not easy, just three clues comprising 3 corners of a rectangle, so we know what the fourth corner is. All rows, columns diagonals and 2-by-2 squares sum to 34
So B1C1 is 34-13, B2C2 is 13, B3C3 is also 21, and therefore A3 is 34-11-21 = 2
But that is the only obvious square, the rest needs quite a bit of logic and trial and retrace/backtrack.
Basically you want to reduce a cell pair to two possibilities, and see what develops if you choose one of them.
For example with A3=2, A2+A4 = 20, so A2 and A4 are at least 4 (ie not 3)
The possibilities are 16+4, 15+5, 14+6, 13+7 (12 and 11 already used)
Suppose the larger number goes in A2 - consider 16 and 15 - then B1+B2 = 6 or 7
1 and 2 are used so 16 is out, and 15 needs B1+B2=3+4 and B1 cannot be either since since C1>16
A2=14 -> B1+B2=8, B1=5,C1=16,B2=3,C2+C3=34-12-14...
12 5 16 1
14 3 10 7
2 15 6 11
No it leads to 6 and 11 again! so A2<>14
and so it goes; 13 needs either B1B2=54 or 63; 54 works out, but the diagonals are 32 and 36 --> no go. So try 63!
try your logic! There may be two solutions. The above only explores A2 > A4, perhaps A4>A2 works too.
Level 9 only has two clues - seems they are opposite corners
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