五年級奧數(shù)專題01小數(shù)的巧算

1、1一小數(shù)的巧算（小數(shù)的巧算（A）年級班姓名得分一、填空題一、填空題1計算1.1353.3465.5577.7689.979=_____.2.計算1.99619.97199.8=_____.3.計算9.899.8999.89999.899999.8=_____.4.計算6.119.228.337.445.554.563.672.781.89=_____.5.計算1.13.35.57.79.911.1113.1315.1517.1719.1

2、9=_____.6.計算2.894.684.686.114.68=_____.??7.計算17.483717.481917.4882=_____.??8.計算1.250.322.5=_____.?9.計算754.715.925=_____.?10.計算28.676732286.7573.40.05=_____.??二、解答題二、解答題11.計算172.46.227240.38?12.計算96310280.0001810.00011???

3、??????個個13.計算12.3423.4534.5645.6756.7867.8978.9189.1291.2314.下面有兩個小數(shù):求abababab.??199419960.00...01050.00...019ab??個個，?3———————————————答案——————————————————————1.27.7852.221.766原式=(20.004)(200.03)(2000.2)=222(0.0040.030.2)

4、=221.7663.111109提示:仿上題.4.49.555.103.25原式=1.1(13…9)1.01(1113…19)??=1.1251.0175??=103.256.46.87.1748原式=17.483717.481917.4882=17.48(371982)=17.48100=17488.1原式=(1.250.8)(0.42.5)???=11?=19.750原式=754.75.3(325)???=75(4.75.3)?=7

5、510?=75010.2867原式=28.67673228.6728.67(200.05)????=28.67(67321)?=28.67100?=286711.原式=172.46.2(17241000)?0.38?=172.46.217240.3810000.38???=172.46.2172.43.8380??=172.4(6.23.8)380?=172.410380?=1724380=210412.181是三位11是兩位相乘后18

6、111=1991是四位三位加兩位是五位因此?1991前面還要添一個0又9631028=1991所以0.00…01810.00…011=0.00…0?1991963個01028個01992個013.9個加數(shù)中十位、個位、十分位、百分位的數(shù)都是1~9，所以原式=11.11(12…9)?=11.1145?=499.9514.a是小數(shù)點后有(199431=)1996位的小數(shù)b是小數(shù)點后有(199621=)1997位小數(shù).ab=0.00…0106

7、9ab=0.00…010311994個01994個0ab=0.00…01995ab=105019=???195553990個0———————————————答案——————————————————————1.2原式=（4.758.25）(9.641.36)=1311=22.17原式=(3.715.29)(4.76.3)(2.740.26)=9113=173.89原式=(5.255.750.125)8?=(110.125)8?=1180.