桌上有6只茶杯,杯口全部朝上,每次翻转其中3只,需翻转多少次,可把它们全部翻成杯口朝下?显然,只需翻转两次.在上面的游戏中,将桌上的茶杯数由6只改成5只,其它条件不变,那末经过若干次翻转,能把它们全部翻成杯口朝下吗?请动手实验一下,结果如何?不妨把杯口朝上记作“+1”,杯口朝 There are 6 tea cups on the table, the cups are all up, each time you flip 3 of them, how many times you need to flip, you can turn them all into cups? Obviously, just flip twice. In the above game, Change the number of teacups on the table from 6 to 5, and other conditions remain the same. Then, after several turnovers, can all of them be turned into cups facing downwards? Please experiment with yourselves. How can the result be? Recorded as “+1” on the cup