2024-2025年五年级下册常州市分数的简便运算期末试卷

2024-2025年五年级下册常州市分数的简便运算期末试卷

一、单项选择题（每题2分，共20分）1.计算\(\frac{1}{5}+\frac{2}{5}\)结果是（）A.\(\frac{3}{10}\)B.\(\frac{3}{5}\)C.\(\frac{2}{5}\)2.\(\frac{7}{9}-\frac{4}{9}\)=（）A.\(\frac{1}{3}\)B.\(\frac{4}{9}\)C.\(\frac{2}{3}\)3.计算\(\frac{1}{3}+\frac{1}{4}\)，通分后分母是（）A.7B.12C.244.与\(\frac{3}{4}+\frac{1}{6}\)计算结果相等的是（）A.\(\frac{9}{12}+\frac{2}{12}\)B.\(\frac{3}{12}+\frac{1}{12}\)C.\(\frac{6}{12}+\frac{4}{12}\)5.\(\frac{5}{8}-\frac{1}{4}\)=（）A.\(\frac{3}{8}\)B.\(\frac{1}{2}\)C.\(\frac{4}{8}\)6.计算\(\frac{2}{7}+\frac{3}{7}+\frac{1}{7}\)的结果是（）A.\(\frac{6}{7}\)B.\(\frac{5}{7}\)C.\(\frac{4}{7}\)7.下面算式结果最小的是（）A.\(\frac{1}{2}+\frac{1}{3}\)B.\(\frac{1}{3}+\frac{1}{4}\)C.\(\frac{1}{4}+\frac{1}{5}\)8.\(\frac{7}{10}-\frac{3}{10}\)的结果用最简分数表示是（）A.\(\frac{2}{5}\)B.\(\frac{4}{10}\)C.\(\frac{1}{5}\)9.计算\(\frac{4}{9}+\frac{1}{3}\)时，\(\frac{1}{3}\)通分后是（）A.\(\frac{3}{9}\)B.\(\frac{2}{9}\)C.\(\frac{4}{9}\)10.\(\frac{3}{5}+\frac{2}{5}-\frac{1}{5}\)=（）A.\(\frac{4}{5}\)B.\(\frac{3}{5}\)C.\(\frac{2}{5}\)二、多项选择题（每题2分，共20分）1.以下能简便计算的分数加法算式有（）A.\(\frac{1}{5}+\frac{3}{5}+\frac{1}{5}\)B.\(\frac{2}{7}+\frac{3}{8}+\frac{5}{8}\)C.\(\frac{4}{9}+\frac{1}{9}+\frac{2}{9}\)D.\(\frac{1}{4}+\frac{3}{7}+\frac{3}{4}\)2.计算\(\frac{1}{3}+\frac{1}{6}+\frac{2}{3}\)可以运用（）A.加法交换律B.加法结合律C.乘法分配律D.减法性质3.下面结果等于\(\frac{1}{2}\)的算式有（）A.\(\frac{3}{4}-\frac{1}{4}\)B.\(\frac{2}{5}+\frac{1}{10}\)C.\(\frac{7}{10}-\frac{2}{10}\)D.\(\frac{4}{8}\)4.分数简便运算中，常见的凑整方法有（）A.同分母分数相加B.把分母化为相同C.找能凑成整数的分数组合D.运用运算定律5.计算\(\frac{5}{9}-\frac{1}{6}-\frac{5}{6}+\frac{4}{9}\)可以先算（）A.\(\frac{5}{9}+\frac{4}{9}\)B.\(\frac{1}{6}+\frac{5}{6}\)C.\(\frac{5}{9}-\frac{1}{6}\)D.\(\frac{5}{9}-\frac{5}{6}\)6.以下分数运算正确的是（）A.\(\frac{3}{5}+\frac{2}{5}=1\)B.\(\frac{7}{8}-\frac{3}{8}=\frac{1}{2}\)C.\(\frac{1}{3}+\frac{1}{9}=\frac{4}{9}\)D.\(\frac{5}{6}-\frac{1}{3}=\frac{1}{2}\)7.能运用加法结合律简便计算的算式有（）A.\(\frac{1}{7}+\frac{2}{7}+\frac{4}{7}\)B.\(\frac{3}{8}+(\frac{5}{8}+\frac{1}{4})\)C.\(\frac{2}{9}+\frac{1}{9}+\frac{3}{9}\)D.\((\frac{1}{5}+\frac{2}{5})+\frac{3}{5}\)8.下面分数减法能简便计算的是（）A.\(\frac{7}{10}-\frac{3}{10}-\frac{1}{10}\)B.\(\frac{5}{8}-(\frac{3}{8}+\frac{1}{8})\)C.\(\frac{9}{11}-\frac{4}{11}-\frac{2}{11}\)D.\(\frac{4}{7}-\frac{2}{7}-\frac{1}{7}\)9.计算\(\frac{2}{3}+\frac{1}{4}+\frac{1}{3}\)运用运算定律后可能是（）A.\((\frac{2}{3}+\frac{1}{3})+\frac{1}{4}\)B.\(\frac{2}{3}+(\frac{1}{4}+\frac{1}{3})\)C.\(\frac{1}{4}+(\frac{2}{3}+\frac{1}{3})\)D.\((\frac{1}{4}+\frac{2}{3})+\frac{1}{3}\)10.分数简便运算中，常用的运算定律有（）A.加法交换律B.加法结合律C.乘法交换律D.乘法结合律三、判断题（每题2分，共20分）1.\(\frac{2}{7}+\frac{3}{7}=\frac{5}{14}\)（）2.计算\(\frac{3}{8}+\frac{1}{4}\)，先通分再计算。（）3.分数运算中，加法交换律和结合律不能同时使用。（）4.\(\frac{5}{6}-\frac{1}{6}=\frac{2}{3}\)（）5.计算\(\frac{1}{5}+\frac{3}{4}\)，通分后的分母是20。（）6.所有分数加减法都要先通分。（）7.\(\frac{7}{9}-\frac{4}{9}=\frac{1}{3}\)（）8.简便运算只能用于整数运算，分数运算不能用。（）9.计算\(\frac{3}{10}+\frac{2}{5}\)，\(\frac{2}{5}\)通分后是\(\frac{4}{10}\)。（）10.\(\frac{1}{2}+\frac{1}{3}=\frac{2}{5}\)（）四、简答题（每题5分，共20分）1.简述分数加法简便运算的方法。答案：观察分数特点，利用加法交换律和结合律，把同分母分数或能凑整的分数先相加，再计算。2.计算\(\frac{3}{8}+\frac{5}{6}+\frac{5}{8}\)，写出过程。答案：\(\frac{3}{8}+\frac{5}{6}+\frac{5}{8}=(\frac{3}{8}+\frac{5}{8})+\frac{5}{6}=1+\frac{5}{6}=\frac{11}{6}\)3.分数减法简便运算要注意什么？答案：注意观察能否运用减法性质，即连续减去两个数等于减去这两个数的和，同时注意通分准确。4.计算\(\frac{7}{9}-\frac{2}{5}-\frac{3}{5}\)。答案：\(\frac{7}{9}-\frac{2}{5}-\frac{3}{5}=\frac{7}{9}-(\frac{2}{5}+\frac{3}{5})=\frac{7}{9}-1=-\frac{2}{9}\)五、讨论题（每题5分，共20分）1.在分数简便运算中，如何快速找到可以凑整的分数组合？答案：先观察分母，同分母分数优先组合；再看分子，通过通分等方式看哪些分数相加或相减能得到整数，如\(\frac{3}{8}\)和\(\frac{5}{8}\)。2.举例说明分数运算中加法交换律和结合律的作用。答案：如\(\frac{1}{4}+\frac{3}{7}+\frac{3}{4}\)，运用加法交换律变为\(\frac{1}{4}+\frac{3}{4}+\frac{3}{7}\)，再结合律\((\frac{1}{4}+\frac{3}{4})+\frac{3}{7}\)，先算\(\frac{1}{4}+\fr