7. A carpenter wishes to cut a wooden $3 \times 3 \times 3$ cube into twenty seven $1 \times 1 \times 1$ cubes. He can do this easily by making 6 cuts through the cube, keeping the pieces together in the cube shape as shown:

What is the minimum number of cuts needed if he is allowed to rearrange the pieces after each cut?
(A) 2 ;
(B) 3;
(C) 4 ;
(D) 5 ;
(E) 6 .
7. Ans: (E)
There is no way to reduce the cuts to fewer than 6: Just consider the middle cube (the one which has no exposed surfaces in the beginning), each of the its sides requires at least one cut.