easy, one minutes i solve the problem
2 M0 a( y# v+ \( Cdivide into half, mean 6/ 6
# L, }7 s! E6 B8 \* p公仔箱論壇take the heavier 6 ping pong
$ P3 ~. u6 k/ J" ]* R9 Zdivide into 3/3, take the heavier 3
% c5 F% ^: x2 Q% S( c$ R% utake the the other 3 that have the equal weight, switch each to measure, the most important things is labeling the ping pong so that we can recognize |