8×75%-3÷3/4 =8×3/4-4=6-4=2 8.5×0.75+7.5×75% =8.5×0.75+7.5×0.75=0.75×(8.5+7.5)=3/4×16=12 5/8-5/6×(1/4-25%)=5/8-5/6×(1/4-1/4)=5/8-5/6×0=5/8-0=5/8 如果帮到你,请记得采纳,O(∩_∩)O谢谢