《2025年口算训练六年级数学上册人教版双色升级版》

$\frac {3}{8}×\frac {2}{15}=$$\frac{1}{20}$
$\frac {12}{17}×\frac {5}{18}=$$\frac{10}{51}$
$\frac {5}{18}×\frac {7}{10}=$$\frac{7}{36}$
$\frac {3}{14}×\frac {5}{6}=$$\frac{5}{28}$
$\frac {2}{3}×\frac {1}{12}=$$\frac{1}{18}$
$\frac {1}{14}×\frac {3}{5}=$$\frac{3}{70}$
$\frac {2}{5}×\frac {1}{8}=$$\frac{1}{20}$
$\frac {5}{16}×\frac {1}{15}=$$\frac{1}{48}$
$\frac {5}{8}×\frac {16}{25}=$$\frac{2}{5}$
$\frac {5}{16}×\frac {8}{19}=$$\frac{5}{38}$
$\frac {3}{7}×\frac {4}{15}=$$\frac{4}{35}$
$\frac {2}{9}×\frac {3}{5}=$$\frac{2}{15}$
$\frac {9}{20}×\frac {5}{18}=$$\frac{1}{8}$

答案： $\frac{3}{8}×\frac{2}{15}=\frac{3×2}{8×15}=\frac{6}{120}=\frac{1}{20}$
$\frac{12}{17}×\frac{5}{18}=\frac{12×5}{17×18}=\frac{60}{306}=\frac{10}{51}$
$\frac{5}{18}×\frac{7}{10}=\frac{5×7}{18×10}=\frac{35}{180}=\frac{7}{36}$
$\frac{3}{14}×\frac{5}{6}=\frac{3×5}{14×6}=\frac{15}{84}=\frac{5}{28}$
$\frac{2}{3}×\frac{1}{12}=\frac{2×1}{3×12}=\frac{2}{36}=\frac{1}{18}$
$\frac{1}{14}×\frac{3}{5}=\frac{1×3}{14×5}=\frac{3}{70}$
$\frac{2}{5}×\frac{1}{8}=\frac{2×1}{5×8}=\frac{2}{40}=\frac{1}{20}$
$\frac{5}{16}×\frac{1}{15}=\frac{5×1}{16×15}=\frac{5}{240}=\frac{1}{48}$
$\frac{5}{8}×\frac{16}{25}=\frac{5×16}{8×25}=\frac{80}{200}=\frac{2}{5}$
$\frac{5}{16}×\frac{8}{19}=\frac{5×8}{16×19}=\frac{40}{304}=\frac{5}{38}$
$\frac{3}{7}×\frac{4}{15}=\frac{3×4}{7×15}=\frac{12}{105}=\frac{4}{35}$
$\frac{2}{9}×\frac{3}{5}=\frac{2×3}{9×5}=\frac{6}{45}=\frac{2}{15}$
$\frac{9}{20}×\frac{5}{18}=\frac{9×5}{20×18}=\frac{45}{360}=\frac{1}{8}$

$12×\frac {2}{3}= $
$\frac {5}{27}×9= $
$4×\frac {5}{11}= $
$\frac {5}{6}×\frac {2}{15}= $
$\frac {3}{5}×\frac {2}{5}= $
$3×\frac {1}{12}= $
$\frac {5}{24}×96= $
$\frac {2}{3}×\frac {5}{12}= $
$16×\frac {3}{4}= $
$\frac {7}{18}×\frac {4}{7}= $
$\frac {5}{22}×\frac {2}{3}= $
$\frac {3}{16}×48= $
$\frac {11}{26}×\frac {2}{5}= $

答案： 解析：
这些题目都是基础的分数乘法口算题，主要考察分数乘法的运算规则，即分子乘分子作为新的分子，分母乘分母作为新的分母，能约分的先约分。
答案：
$12 × \frac{2}{3} = 8$
$\frac{5}{27} × 9 = \frac{5}{3}$
$4 × \frac{5}{11} = \frac{20}{11}$
$\frac{5}{6} × \frac{2}{15} = \frac{1}{9}$
$\frac{3}{5} × \frac{2}{5} = \frac{6}{25}$
$3 × \frac{1}{12} = \frac{1}{4}$
$\frac{5}{24} × 96 = 20$
$\frac{2}{3} × \frac{5}{12} = \frac{5}{18}$
$16 × \frac{3}{4} = 12$
$\frac{7}{18} × \frac{4}{7} = \frac{2}{9}$
$\frac{5}{22} × \frac{2}{3} = \frac{5}{33}$
$\frac{3}{16} × 48 = 9$
$\frac{11}{26} × \frac{2}{5} = \frac{11}{65}$

$300×(1+\frac {2}{5})=$420
$60×(1+\frac {2}{3})=$100
$450×(1+\frac {1}{5})=$540
$80×(1+\frac {3}{4})=$140
$70×(1+\frac {1}{5})=$84
$120×(1+\frac {5}{12})=$170
$240×(1+\frac {3}{4})=$420
$160×(1+\frac {5}{8})=$260
$280×(1+\frac {3}{7})=$400
$350×(1+\frac {4}{5})=$630
$720×(1-\frac {5}{9})=$320
$250×(1+\frac {2}{5})=$350
$540×(1-\frac {7}{9})=$120

答案： 解析：
这些问题都是基础的数学运算问题，主要考察的是乘法分配律的应用。
对于形如 $a × (1 + \frac{b}{c})$ 的表达式，可以将其拆分为 $a + a × \frac{b}{c}$，然后进行计算。
同样，对于形如 $a × (1 - \frac{b}{c})$ 的表达式，可以将其拆分为 $a - a × \frac{b}{c}$，然后进行计算。
答案：
$300 × (1 + \frac{2}{5})$
$= 300 + 300 × \frac{2}{5}$
$= 300 + 120$
$= 420$
$60 × (1 + \frac{2}{3})$
$= 60 + 60 × \frac{2}{3}$
$= 60 + 40$
$= 100$
$450 × (1 + \frac{1}{5})$
$= 450 + 450 × \frac{1}{5}$
$= 450 + 90$
$= 540$
$80 × (1 + \frac{3}{4})$
$= 80 + 80 × \frac{3}{4}$
$= 80 + 60$
$= 140$
$70 × (1 + \frac{1}{5})$
$= 70 + 70 × \frac{1}{5}$
$= 70 + 14$
$= 84$
$120 × (1 + \frac{5}{12})$
$= 120 + 120 × \frac{5}{12}$
$= 120 + 50$
$= 170$
$240 × (1 + \frac{3}{4})$
$= 240 + 240 × \frac{3}{4}$
$= 240 + 180$
$= 420$
$160 × (1 + \frac{5}{8})$
$= 160 + 160 × \frac{5}{8}$
$= 160 + 100$
$= 260$
$280 × (1 + \frac{3}{7})$
$= 280 + 280 × \frac{3}{7}$
$= 280 + 120$
$= 400$
$350 × (1 + \frac{4}{5})$
$= 350 + 350 × \frac{4}{5}$
$= 350 + 280$
$= 630$
$720 × (1 - \frac{5}{9})$
$= 720 - 720 × \frac{5}{9}$
$= 720 - 400$
$= 320$
$250 × (1 + \frac{2}{5})$
$= 250 + 250 × \frac{2}{5}$
$= 250 + 100$
$= 350$
$540 × (1 - \frac{7}{9})$
$= 540 - 540 × \frac{7}{9}$
$= 540 - 420$
$= 120$