以下是100道较难的分数乘法计算题，涵盖分数乘整数、分数乘分数、分数乘减法规律及应用题，适合六年级及以上学生练习：
一、基础运算类（20道）
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$\frac{3}{4} \times 8 = \frac{3}{4} \times \frac{8}{1} = \frac{24}{4} = 6$
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$\frac{5}{8} \times \frac{4}{5} = \frac{20}{40} = \frac{1}{2}$
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$\frac{7}{9} \times \frac{3}{7} = \frac{21}{63} = \frac{1}{3}$
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$\frac{2}{5} \times 10 = \frac{2}{5} \times \frac{10}{1} = \frac{20}{5} = 4$
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$\frac{11}{12} \times \frac{6}{11} = \frac{66}{132} = \frac{1}{2}$
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$\frac{4}{7} \times \frac{7}{4} = 1$
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$\frac{3}{10} \times 5 = \frac{3}{10} \times \frac{5}{1} = \frac{15}{10} = 1.5$
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$\frac{8}{9} \times \frac{9}{8} = 1$
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$\frac{5}{6} \times \frac{3}{5} = \frac{15}{30} = \frac{1}{2}$
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$\frac{2}{3} \times 9 = \frac{2}{3} \times \frac{9}{1} = \frac{18}{3} = 6$
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$\frac{7}{8} \times \frac{4}{7} = \frac{28}{56} = \frac{1}{2}$
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$\frac{3}{5} \times \frac{5}{3} = 1$
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$\frac{1}{4} \times 16 = \frac{1}{4} \times \frac{16}{1} = 4$
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$\frac{6}{7} \times \frac{7}{6} = 1$
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$\frac{2}{9} \times 18 = \frac{2}{9} \times \frac{18}{1} = 4$
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$\frac{5}{12} \times 6 = \frac{5}{12} \times \frac{6}{1} = \frac{30}{12} = 2.5$
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$\frac{8}{11} \times \frac{11}{8} = 1$
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$\frac{3}{14} \times 7 = \frac{21}{98} = \frac{3}{14}$
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$\frac{7}{10} \times 5 = \frac{35}{10} = 3.5$
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$\frac{4}{15} \times 15 = \frac{4}{15} \times \frac{15}{1} = 4$
二、分数乘减法规律类（20道）
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$\frac{3}{5} \times \frac{1}{2} - \frac{3}{5} \times \frac{1}{3} = \frac{3}{5} \times （\frac{1}{2} - \frac{1}{3}） = \frac{3}{5} \times \frac{1}{6} = \frac{1}{10}$
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$\frac{4}{7} \times \frac{3}{4} + \frac{4}{7} \times \frac{1}{4} = \frac{4}{7} \times （\frac{3}{4} + \frac{1}{4}） = \frac{4}{7} \times 1 = \frac{4}{7}$
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$\frac{5}{9} \times \frac{2}{5} - \frac{5}{9} \times \frac{1}{5} = \frac{5}{9} \times （\frac{2}{5} - \frac{1}{5}） = \frac{5}{9} \times \frac{1}{5} = \frac{