《2025年口算训练六年级数学上册人教版双色升级版》

$\frac {2}{7}×\frac {6}{7}= $
$\frac {7}{8}×\frac {3}{8}= $
$\frac {1}{4}+\frac {1}{5}= $
$\frac {1}{4}-\frac {1}{5}= $
$\frac {1}{6}×\frac {1}{7}= $
$\frac {1}{6}+\frac {1}{7}= $
$\frac {1}{6}-\frac {1}{7}= $
$\frac {1}{5}×\frac {5}{33}= $
$\frac {20}{21}×\frac {14}{31}= $
$\frac {4}{5}×\frac {1}{2}= $
$\frac {9}{10}×\frac {2}{3}= $
$\frac {1}{8}+\frac {1}{9}= $
$\frac {1}{8}-\frac {1}{9}= $

答案： $\frac{2}{7}×\frac{6}{7}=\frac{12}{49}$
$\frac{7}{8}×\frac{3}{8}=\frac{21}{64}$
$\frac{1}{4}+\frac{1}{5}=\frac{5}{20}+\frac{4}{20}=\frac{9}{20}$
$\frac{1}{4}-\frac{1}{5}=\frac{5}{20}-\frac{4}{20}=\frac{1}{20}$
$\frac{1}{6}×\frac{1}{7}=\frac{1}{42}$
$\frac{1}{6}+\frac{1}{7}=\frac{7}{42}+\frac{6}{42}=\frac{13}{42}$
$\frac{1}{6}-\frac{1}{7}=\frac{7}{42}-\frac{6}{42}=\frac{1}{42}$
$\frac{1}{5}×\frac{5}{33}=\frac{1}{33}$
$\frac{20}{21}×\frac{14}{31}=\frac{40}{93}$
$\frac{4}{5}×\frac{1}{2}=\frac{2}{5}$
$\frac{9}{10}×\frac{2}{3}=\frac{3}{5}$
$\frac{1}{8}+\frac{1}{9}=\frac{9}{72}+\frac{8}{72}=\frac{17}{72}$
$\frac{1}{8}-\frac{1}{9}=\frac{9}{72}-\frac{8}{72}=\frac{1}{72}$

$\frac {5}{6}×\frac {3}{7}= $
$\frac {5}{6}×\frac {1}{5}= $
$\frac {3}{4}×\frac {8}{13}= $
$\frac {2}{9}×\frac {3}{7}= $
$\frac {2}{7}×\frac {7}{17}= $
$1-\frac {1}{2}×\frac {1}{3}= $
$1-(\frac {1}{2}+\frac {1}{3})= $
$(\frac {1}{2}-\frac {1}{3})×6= $
$1-\frac {1}{4}×\frac {1}{5}= $
$\frac {4}{5}×\frac {3}{4}= $
$\frac {11}{26}×\frac {13}{22}= $
$\frac {9}{16}×\frac {5}{18}= $
$\frac {7}{27}×\frac {3}{7}= $

答案： 解析：
这些题目都是分数乘法的练习，需要掌握分数乘法的运算规则，即分子乘分子，分母乘分母，然后化简得到最简形式。对于涉及加减的表达式，需要先计算乘法，再进行加减运算。
答案：
$\frac{5}{6} × \frac{3}{7} = \frac{5 × 3}{6 × 7} = \frac{15}{42} = \frac{5}{14}$；
$\frac{5}{6} × \frac{1}{5} = \frac{5 × 1}{6 × 5} = \frac{5}{30} = \frac{1}{6}$；
$\frac{3}{4} × \frac{8}{13} = \frac{3 × 8}{4 × 13} = \frac{24}{52} = \frac{6}{13}$；
$\frac{2}{9} × \frac{3}{7} = \frac{2 × 3}{9 × 7} = \frac{6}{63} = \frac{2}{21}$；
$\frac{2}{7} × \frac{7}{17} = \frac{2 × 7}{7 × 17} = \frac{14}{119} = \frac{2}{17}$；
$1 - \frac{1}{2} × \frac{1}{3} = 1 - \frac{1 × 1}{2 × 3} = 1 - \frac{1}{6} = \frac{6}{6} - \frac{1}{6} = \frac{5}{6}$；
$1 - (\frac{1}{2} + \frac{1}{3}) = 1 - \frac{3 + 2}{6} = 1 - \frac{5}{6} = \frac{6}{6} - \frac{5}{6} = \frac{1}{6}$；
$(\frac{1}{2} - \frac{1}{3}) × 6 = \frac{3 - 2}{6} × 6 = \frac{1}{6} × 6 = 1$；
$1 - \frac{1}{4} × \frac{1}{5} = 1 - \frac{1 × 1}{4 × 5} = 1 - \frac{1}{20} = \frac{20}{20} - \frac{1}{20} = \frac{19}{20}$；
$\frac{4}{5} × \frac{3}{4} = \frac{4 × 3}{5 × 4} = \frac{12}{20} = \frac{3}{5}$；
$\frac{11}{26} × \frac{13}{22} = \frac{11 × 13}{26 × 22} = \frac{143}{572} = \frac{1}{4}$；
$\frac{9}{16} × \frac{5}{18} = \frac{9 × 5}{16 × 18} = \frac{45}{288} = \frac{5}{32}$；
$\frac{7}{27} × \frac{3}{7} = \frac{7 × 3}{27 × 7} = \frac{21}{189} = \frac{1}{9}$。

$18×\frac {5}{6}=$15
$2.5×\frac {3}{5}=$1.5
$4.5×\frac {7}{9}=$3.5
$\frac {7}{20}×0.1=$0.035
$\frac {5}{8}×0.4=$0.25
$3.6×\frac {5}{6}=$3
$\frac {3}{4}×\frac {2}{5}×15=$$\frac{9}{2}$ (或者写作4.5)
$\frac {5}{6}×\frac {2}{15}×3=$$\frac{1}{3}$
$(\frac {3}{4}+\frac {1}{4})×\frac {7}{8}=$$\frac{7}{8}$
$\frac {2}{15}×(\frac {1}{8}×15)=$$\frac{1}{4}$
$\frac {3}{14}×\frac {5}{6}×7=$$\frac{5}{4}$ (或者写作1.25)
$5.6×\frac {3}{8}=$2.1
$\frac {2}{7}×4.9=$1.4

答案： 解析：
这些题目都是基础的数学运算题目，主要考察的是分数、小数和整数的乘法运算。
对于分数与整数的乘法，我们直接将整数与分数的分子相乘，然后除以分数的分母。
对于分数与小数的乘法，我们可以先将小数转换为分数，然后进行乘法运算，或者将分数转换为小数后进行乘法运算，注意小数点的位置。
对于多个分数的乘法，我们直接将它们的分子相乘得到新的分子，分母相乘得到新的分母。
对于加法与乘法的混合运算，我们需要先计算括号内的加法，然后再进行乘法。
答案：
$18 × \frac{5}{6} = 15$
$2.5 × \frac{3}{5} = 1.5$
$4.5 × \frac{7}{9} = 3.5$
$\frac{7}{20} × 0.1 = 0.035$
$\frac{5}{8} × 0.4 = 0.25$
$3.6 × \frac{5}{6} = 3$
$\frac{3}{4} × \frac{2}{5} × 15 = \frac{9}{2}$ (或者写作4.5)
$\frac{5}{6} × \frac{2}{15} × 3 = \frac{1}{3}$
$(\frac{3}{4} + \frac{1}{4}) × \frac{7}{8} = \frac{7}{8}$
$\frac{2}{15} × (\frac{1}{8} × 15) = \frac{1}{4}$
$\frac{3}{14} × \frac{5}{6} × 7 = \frac{5}{4}$ (或者写作1.25)
$5.6 × \frac{3}{8} = 2.1$
$\frac{2}{7} × 4.9 = 1.4$