【0.75-(2又1/3-1又1/9)/4】/【(1又1/2+2又2/3)/2又1/2-5/6】=[3／4－﹙1又2/9﹚／4]/(4又1/6)/2又1/2-5/6】=﹙3／4-11／36﹚／﹙25／6·2／5－5/6﹚=﹙4／9﹚／(5/6﹚=8／15
解：原式=（3/4-11/36）/(5/3-5/6) =(4/9)/(5/6)=8/15
