0.9÷0.8÷0.4÷1.25÷0.25 1.7×45＋31×8.5 11.1 ×71＋62×2.9＋2.9×47

0.9/((0.8*1.25)*(0.4*0.25))=9
1.7×45＋31×8.5 = 1.7*45 +1.7*5*31=1.7* (45+155)=1.7*200=340
11.1 ×71＋62×2.9＋2.9×47 = 11.1*71 + 2.9*(62+49) = 111*7.1+2.9*111=111*(7.1+2.9) =1110