复习与回顾：整数乘法的简便运算（40＋8）×2515×（40－8）36×34＋36×6628×18－8×2856×10125×41125×7925×3983＋83×99125×81－125350×48-35×8075×230+250×23乘法交换律与结合律的运用。4.56×0.4×2.512.5×2.7×0.812.5×32×0.252.5×3212.5×5625×0.36乘法分配律的运用。12.5×8.899×0.353.7×1.8－2.7×1.895.7×0.28＋6.3×0.28－0.28×21.08×9＋1.08比较乘法结合律与分配律在简便运算时的区别。下面各题用两种方法简算。12.5×8812.5×880.25×480.25×4812.5×8812.5×880.25×480.25×48变一变，能简算。48×0.56＋44×0.480.279×343＋0.657×2790.264×519＋264×0.4819.16×1.53－0.053×91.6拓展提高。99.99×0.8＋11.11×2.8314×0.043＋3.14×7.2－31.4×0.15完全独立练习。5×1.03×0.232×1.250.45×9953×10.14.2×6.51＋3.49×4.29.99×2.22＋3.33×3.340.125×9612.5×10.8（20－4）×0.2545×21－50×2.145×1.58＋5.5×15.825×7.3×0.4练习作业0.25×8.5×412.5×0.96×0.80.25×0.73×44.8×10.11.25×2.5×32小数乘法的简便运算表面上看来，左右两边没有相同的因数，不能使用乘法分配律。4.36×12.5×80.25×16.2×4(1.25－0.125)×80.39×1993.2×0.25×12.53.6×1020.32×4033.65×10.10.85×9.93.72×3.5＋6.28×3.515.6×2.1－15.6×1.14.8×7.8＋78×0.5256.5×99＋56.51.87×9.9＋0.1877.09×10.8－0.8×7.094.2×99＋4.23.8×4.56＋3.83×5.449.7×99＋9.727.5×3.7－7.5×3.73.14×0.68＋31.4×0.0327.2×0.2＋2.4×1.45.4×11-5.43.9×2.7＋3.9×7.312.7×9.9＋1.270.65×1012.3×16+2.3×23+2.33.65×4.7－36.5×0.3746×57＋23×86101×0.87-0.91×878.9×1.017.6×0.8＋0.2×7.61.28×8.6＋0.72×8.610.7×16.1-15.1×10.70.25×362.22×9.9+6.66×6.710.6×0.35－9.6×0.357.74×（2.8－1.3）＋1.5×2.26小数乘法练习题一、列竖式计算.0.26×73.105×1863.08×2511.4×190.59×44.3×280.08×12524×0.525×0.1254.87×10028×1.50.82×23.95×422.073×15二、口算0.8×25=7.4×100=0.7×5=0.9×11=0.96×0=0.02×500=12.5×8=0.3×10=1.4×3=1.12×2=0.39×10=4.1×6=1.9×8=2.3×5=三、根据28×65=1820，直接写出下面各题的积0.28×65=28×6.5=28×0.65=2.8×6.5=0.28×0.65=2.8×0.65=四、根据56×125=7000，写出下面各题的积。0.56×125=5.6×1.25=560×12.5=5600×0.125=五、列式计算.并带竖式(1)12个35.07元是多少元?(2)2.39的8倍是多少?(3)25个10.04是多少?(4)3.8的15倍是多少?六、一个正方形的边长是19.5米，它的周长多少米?七、一种日记本的单价是2.38元，买15个要付多少元钱?用简便方法计算4.8+8.63+5.2+0.375.93+0.19+2.811.76+0.195+3.242.35+1.713+0.287+7.651.57+0.245+7.436.02+3.6+1.98八、一个奶牛场八月份产奶18.5吨。九月份产的奶是八月份的2.4倍。九月份产奶多少吨?九、小明看见远处打闪以后，经过4秒听到雷声。已知雷声在空气中每秒传播0.33千米，打闪的地方离小明有多远?十、一个长方形宽是2分米，比长短1.8分米，这个长方形的面积是多少平方分米？十一、瓶里装满水，连瓶称1.2千克，把瓶里的水倒去一半，再连瓶称是750克。瓶重多少千克？①甲有存款4000元，乙有存款2400元，乙从存款中取出一些后，甲的存款正好是乙现在的5倍。乙取出多少元钱？②有一堆煤，如果用甲种车一次运完，需要36辆;如果用乙种车一次运完，需要45辆。已知甲种车比乙种车每辆多运1.5吨。问这批煤共有多少吨？0.134+2.66+0.8661.27+3.9+0.73+16.13.07－0.38－1.628－2.45－1.5523.4－0.8－13.4－7.20.32×4030.25×3612.7－（3.7＋0.84）36.54－1.76－4.547.6×0.8＋0.2×7.60.85×1990.25×8.5×41.28×8.6＋0.72×8.612.5×0.96×0.810.4－9.6×0.350.8×（4.3×1.25）3.12＋3.12×9928.6×101－28.6（4.23＋6.17）×0.80.86×15.7－0.86×14.72.4×10214－7.32－2.682.64＋8.67＋7.36＋11.332.31×1.2×0.5（2.5－0.25）×0.49.16×1.5－0.5×9.163.6－3.6×0.54.5÷1.84.2÷3.5930÷0.6÷563.4÷2.5÷0.44.9÷1.43.9÷（1.3×5）（7.7＋1.54）÷0.72.5×2.42.7÷450.35×1.25×2×0.832.4×0.9＋0.1×32.415÷0.2570÷2815÷（0.15×0.4）4.25÷2.5×9.9＋0.170.25×8.5×412.5×0.96×0.80.25×0.73×44.36×12.5×80.25×16.2×41.25×2.5×323.2×0.25×12.50.25×36(1.25－0.125)×84.8×10.13.6×1020.39×1990.85×9.90.32×4033.65×10.13.72×3.5＋6.28×3.515.6×2.1－15.6×1.14.8×7.8＋78×0.5256.5×99＋56.57.09×10.8－0.8×7.091.87×9.9＋0.1874.2×99＋4.23.8×4.56＋3.83×5.449.7×99＋9.727.5×3.7－7.5×3.73.14×0.68＋31.4×0.0327.2×0.2＋2.4×1.47.74×（2.8－1.3）＋1.5×2.263.9×2.7＋3.9×7.312.7×9.9＋1.275.4×11-5.42.3×16+2.3×23+2.33.65×4.7－36.5×0.3746×57＋23×86101×0.87-0.91×8710.7×16.1-15.1×10.77.6×0.8＋0.2×7.61.28×8.6＋0.72×8.610.6×0.35－9.6×0.358.9×1.010.65×1012.22×9.9+6.66×6.7
