1.脱式计算,能简便计算的要简便计算。 25×7.2×0.4÷0.9 =25×0.4×7.2÷0.9 =(25×0.4)×(7.2÷0.9) =10×8 =80 4.04×2.5 =1.01×4×2.5 =1.01×(4×2.5) =1.01×10 =10.1 7.3×9.9 =7.3×(10-0.1) =7.3×10-7.3×0.1 =73-0.73 =72.27 2.脱式计算,能简便计算的要简便计算。 4.57÷1.25÷8 =4.57÷(1.25×8) =4.57÷10 =0.457 8.6×19+8.6 =8.6×(19+1) =8.6×20 =172 0.8×(6-8.5÷1.7) =0.8×(6-5) =0.8×1 =0.8 3.脱式计算,能简便计算的要简便计算。 1.1÷1.25 =(1.1×8)÷(1.25×8) =8.8÷10 =0.88 267÷1.25÷8 =267÷(1.25×8) =267÷10 =26.7 3.39÷15÷0.2 =3.39÷(15×0.2) =3.39÷3 =1.13
