1.6/11×9/8+9/8×5/11 =9/8×(6/11+5/11) =9/8×1 =9/8 (8-6/13-7/13)×2/7=[8-(6/13+7/13)]×2/7=[8-1]×2/7=7×2/7=2(5/6+3/4)×12 =5/6×12+3/4×12 =10+9 =19 4/7×1/6+3/7÷6=4/7×1/6+3/7×1/6=1/6×(4/7+3/7)=1/6×1=1/62. 360×2/9+360×1/4=170(米)答:两周一共修了170米。3. 72×5/6 -9=51(枚)答:李红 |