被2整除的有2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50.
被5整除的有5,10,15,20,25,30,35,40,45,50.
被2和5整除的有10,20,30,40,50.
被3和5整除的有15,30,45.