把1/5×7.5=3/7×3.5改成比例能写出8个比例：1/5:3/7=3.5:7.51/5:3.5=3/7:7.57.5:3/7=3.5:1/57.5:3.5=3/7:1/53/7:1/5=7.5:3.53/7:7.5=1/5:3.53.5:1/5=7.5:3/73.5:7.5=1/5:3/7
