1、第1招 巧算小数乘法 BS 四年级下册 简算：0.99991.80.11117.2 0.11119经典例题 90.80.11119解法一：0.99991.80.11117.20.111191.80.11117.20.1111(16.27.2)0.111190.9999 规范解答：解法二：0.99991.80.11117.20.99991.80.111190.80.9999(1.80.8)0.999913提示：点击进入题组训练运用乘法分配律简算综合运用乘法运算律简算运用转化思想简算根据数的特点通过变形简算245678910111213141013.60.113.61361.36134.641.9
2、.913.6 运用乘法分配律简算技 巧 1(100.1)13.62.6.592.457.556.59 6.59(2.457.55)6.591065.93.4.21.014.2(10.01)4.214.20.014.20.0424.2424.452.152.1(455)2.1402.1845.4.78994.784.78(991)4.781004786.18.810118.8 18.8(1011)18.81001880综合运用乘法运算律简算技 巧 2 7.用两种不同的方法简算。(1)1.257.2方法一：1.257.21.2580.9100.99方法二：1.257.21.25(80.8)1.25
3、81.250.81019(2)2.54.44方法一：2.54.442.541.11101.1111.1方法二：2.54.442.5(40.40.04)2.542.50.42.50.041010.111.18.0.550.60.1170.1130.117 0.11(37)0.11101.1运用转化思想简算技 巧 3 0.1150.60.1179.0.9910.19.90.010.9910.10.990.1 0.9910.10.99100.010.99(10.10.1)0.99109.910.19.9837199.82.39.998019.983719.982319.9840 19.983719.
4、98102.39.9924019.98(372340)19.98100199811.1.991990.991.991.9999 1.99(199)1.991001991.991.991000.9912.0.079525007950.747.957950.257950.740.01795 795(0.250.740.01)79517950.079510000.257950.740.0179513.400.6720030.4200.314200.34 200.3(144)200.3102003200.327200.3100.4根据数的特点通过变形简算技 巧 3 14.20022001.200120012002.2002200220011.0001200120021.0001 0
