put 3 balls on each side,
5 s3 F( B/ j% Q$ e& atvb now,tvbnow,bttvbif balance, we can prove that all 6 balls on the 天平 is normal,
5 |6 v/ A" f: {( ~( Gif not balance, we can prove that the 6 balls outside the 天平 is normal.tvb now,tvbnow,bttvb: R% s) A- Z+ [( H- B0 ^7 o
then use the proved-normal ball on one side and put the other ball on other side
8 e( A# D6 C h5 [! |to determine the abnormal is heavy and light |