1/18 = 2/36 = 1/36 + 1/36 ,a=36,b=36
1/18 = 3/54 = 2/54+1/54 = 1/27 + 1/54,a=27,b=54
1/18 = 4/72 = 1/24 + 1/72,a=24,b=72
1/18 = 5/90 = 1/30 + 1/45,a=30,b=45
好多好多,根据我这个方法就好了