1、小数乘法简便运算分类拓展提高例题+习题小数乘法简便运算-拓展提高一、 比较乘法结合律与分配律在简便运算时的区别。例题:下面各题用两种方法简算。12.588 0.254812.588 0.2548练习:0.125400 2.510.8 0.2540.4二、 变一变,能简算。480.56440.48 4.87.8780.52 试一试:0.2793430.657279 0.2645192640.481 9.161.530.05391.6 199.719.98-199.819.9626.425-26250 4.820.59+0.414.82三、 同类提高。变一变,能简算。3140.0433.147.2
2、31.40.15 0.24528+24.53+2.457.222.058.2-20.054.5-20.053.7 4.8252-4812.2-480 四、综合提高。99.990.811.112.8 197237+197.21.9-98670.3888.88.7+11.29.9-11.21.2 6.250.16+3.70.84+25.50.0841.255.6+2.504.4 0.2540.4+0.12510.8四、 完全独立练习。9.992.223.333.34 4.26.5134.90.42 4521502.1 451.585.515.8 200.320.05-20.03200.4 4.83
3、0.59+0.411.59-0.3245.9五、乘除法巧算 计算:3.60.751.2(1.5240.18) 点拨 : 如果分别算出除号两边的积,再求商,则非常麻烦,仔细观察被除数中的因数和除数中的因数存在的关系,应用除法的性质去掉括号,改变运算顺序,就能使计算简便。用简便方法计算下面各题。7.24.59.3(1.81.53.1) 12.67.62.321.91.42.9看看你能摘几颗“”。用简便方法计算下面各题。 0.2540.4+0.12510.8 200.320.05-20.03200.4(3)0.255(851.011.01) 4.830.59+0.411.59-0.3245.92.19+6.48+0.51-1.38-5.48-0.62 1.250.2532329.18.90.2+8.80.2+8.70.2+8.10.2【课后作业】简便计算0.3425193420.481 351.536.515.3 199.719.98-199.819.96 100.320.05-10.03200.4 5110.0435.117.251.10.15 1.9252-1912.2-190 99.990.811.112.8 0.2540.4+0.12510.89.992.223.333.34 12.67.62.321.91.42.9 6.250.16+3.70.84+25.50.084