五年级奥数小数的巧算练习题.doc

五年级奥数小数的巧算练习题1 1.135+3.346+5.557+7.768+9.9792. 1.996+19.97+199.83. 6.11+9.22+8.33+7.44+5.55+4.56+3.67+2.78+1.894. 1.1+3.3+5.5+7.7+9.9+11.11+13.13+15.15+17.17+19.195. 2.894.68+4.68 6.11+4.686. 17.4837-17.4819+17.48827. 1.25 0.322.58. 754.7+15.9259. 28.6767+32286.7+573.4 0.0510. 172.46.2+27240.381028个0963个011. 0.0001810.0001112. 12.34+23.45+34.56+45.67+56.78+67.89+78.91+89.12+91.231994个01996个013.a= 0.000105 b=0.00019 计算a+b a-b ab ab14. 4.75-9.64+8.25-1.3615. 3.71-2.74+4.7+5.29-0.26+6.316. (5.25+0.125+5.75) 817. 34.58.23-34.5+2.7734.518. 6.250.16+2640.0625+5.26.25+0.6252019. 0.035935+0.035+30.035+0.07610.520. 19.9837-199.81.9+19980.8221. 13.59.9+6.5+5.7510.122. 0.1250.250.56423. 11.843-8600.0924. 32.14+64.280.53780.25+0.537864.280.75-864.280.1250.537825. 0.88812573+999325. 1998+199.8+19.98+1.9981996个02000个026.a= 0.000125 b=0.0008 计算a+b a-b ab ab五年级奥数小数的巧算练习题答案 1. 27.785 2. 221.766 原式=(2-0.004)+(20-0.03)+(200-0.2) =222-(0.004+0.03+0.2) =221.766 3. 111109 提示:仿上题. 4. 49.55 5. 103.25 原式=1.1(1+3+9)+1.01(11+13+19) =1.125+1.0175 =103.25 6. 46.8 7. 1748 原式=17.4837-17.4819+17.4882 =17.48(37-19+82) =17.48100 =1748 8. 1 原式=(1.250.8)(0.42.5) =11 =19. 750 原式=754.7+5.3(325) =75(4.7+5.3) =7510=750 10. 2867 原式=28.6767+3228.67+28.67(200.05) =28.67(67+32+1) =28.67100 =2867