5/12×9×4/15=（5/12x4/15）x9=1/9x9=1希望能帮到你！
6.8÷0.17×1.6 =0.68÷0.17×16 =4×16 =64 7.08-0.8×1.25 =7.08-(4/5)×(5/4) =7.08-1 =6.08 65.8÷9.4+12.9 =7+12.9 =19.9
5/12×9×4/15=（5/15）X9X(4/12)=1/3X9X1/3=1
就是等于1。
