56/（5.6*4）=(56*10)/（5.6*4*10）=(56*10)/（56*4）=10/4=2.58.4/9+1.6/4=8.4/9+0.4/1=8.4/9+3.6/9=12/9=4/34.68-（1.68-0.32）=4.68-1.68+0.32=3+0.32=3.327.3/4+2.7*0.25=7.3/4+2.7*1/4=7.3/4+2.7/4=10/4=2.5....怎么觉得有些题答案好像不对~哪一个8.4/6+1.6/4=1.4+0.4=1.8