四年级数学【小数的简便运算】计算例题

四年级数学【小数的简便运算】计算例题


简介:
399.6×9-1998×0.8 =399.6×9-1998×2×0.4 =399.6×9-399.6×4 =399.6×5 =1998 12.9÷0.72+43.5÷3.6 =(12.9×5)÷(0.72×5)+43.5÷3.6 =64.5÷3.6+43.5÷3.6 =(64.5+43.5)÷3.6 =30 49.5×13.5-0.5×49.5+50.5×13 =49.5×(13.5-0.5)+50.5×13 =49.5×13+50.5×13 =(49.5+50.5)×13 =1300 36×2.54+1.8×49.2 =1.8×20×2.54+1.8×49.2 =1.8×(20×2.54)+1.8×49.2 =1.8×(50.8+49.2) =1.8×100 =180 1.1×1.1×11-1.1×1.1-1.1 =1.1×1.1×(11-1)-1.1 =1.1×11-1.1 =1.1×(11-1) =11 1992×27.5+1982×72.5 =(1982+10)×27.5+1982×72.5 =1982×(27.5+72.5)+10×27.5 =198200+275 =198475 100×9.5×0.98+9.5×2 =100×0.98×9.5+9.5×2 =9.5×(98+2) =9.5×100 =950 28×11.11+99.99×8 =28×11.11+11.11×9×8 =28×11.11+11.11×(9×8) =11.11×(28+72) =11.11×100 =1111