Hello....
We have a keyboard at home to hang our 25 keys, the board is devided into 25 squares,the keys are numbered 1 to 25 and they should be in this arrengement :
1 3 5 7 9
19 17 15 13 11
21 23 25 2 4
14 12 10 8 6
16 18 20 22 24
my brother likes mathmatics,one day he changed the arrengement of the keys ,so that,if we add numbers of each five keys in a raw(vertically.horizontally,or diagonally)will always be the same , but he didn`t notice that my two keys are still in their places!.
which keys are mine?