3:6=5:10
6:3=10:5
5:10=3:6
10:5=6:3
3x10=5x6
10x3=5x6
5x6=3x10
6x5=3x10后面4个。。。。不对啊后面4个不算的话，就只能组成4组比例。（后面是反比例）\\\\\\