计算下面各题,能简便计算的要简算
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| (1)156×l0l-156 =156×(l0l-1) =156×100 =15600 (2)404×25 =(400+4)×25 =400×25+4×25 =10000+100 =10100 (3)23×44+23×57-23 =23×(44+57-1) =23×100 =2300 (4)99×38 =(100-1)×38 =100×38-38 =3800-38 =3762 (5)25×32×125 =25×4×8×125 =(25×4)×(8×125) =100×1000 =100000 (6)400×[(270+80)÷7] =400×[350÷7] =400×50 =20000 (7)165+299 =165+(300-1) =465-1 =464 (8)47×99+47 =47×(99+1) =47×100 =4700 (9)630÷18÷5 =630÷(18×5) =630÷90 =4 (10)(730-80÷2)÷23 =(730-40)÷23 =690÷23 =30 (11)525-20×5+25 =525-100+25 =(525+25)-100 =550-100 =450 (12)37+125+63+175 =(37+63)+(125+175) =100+300 =400 (13)149×45-45×49 =(149-49)×45 =100×45 =4500 (14)1800÷25÷4 =1800÷(25×4) =1800÷100 =18 (15)32×(50+4) =32×50+4×32 =1600+128 =1728 |
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