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第69页

信息发布者：

$ \frac {5}{8}$

$ \frac {7}{12}$

$ \frac {10}{7}$

$ \frac {1}{7}$

$\frac{1}{3}+\frac{2}{3}\div\frac{3}{4}$

$=\frac{1}{3}+\frac{2}{3}\times\frac{4}{3}$

$=\frac{1}{3}+\frac{8}{9}$

$=\frac{3}{9}+\frac{8}{9}$

$=\frac{11}{9}$

$\frac{2}{5}\times(\frac{5}{6}-\frac{3}{4})$

$=\frac{2}{5}\times(\frac{10}{12}-\frac{9}{12})$

$=\frac{2}{5}\times\frac{1}{12}$

$=\frac{1}{30}$

 $\frac{9}{5}\times\frac{2}{3}-\frac{4}{5}\div\frac{8}{7}$

 $=\frac{6}{5}-\frac{4}{5}\times\frac{7}{8}$

 $=\frac{6}{5}-\frac{7}{10}$

 $=\frac{12}{10}-\frac{7}{10}$

 $=\frac{1}{2}$

$42\times(\frac{1}{6}+\frac{1}{7})$

$=42\times\frac{1}{6}+42\times\frac{1}{7}$

$=7+6$

$=13$

$\frac{2}{9}\times\frac{1}{4}+\frac{7}{9}\div4$

$=\frac{2}{9}\times\frac{1}{4}+\frac{7}{9}\times\frac{1}{4}$

$=(\frac{2}{9}+\frac{7}{9})\times\frac{1}{4}$

$=1\times\frac{1}{4}$

$=\frac{1}{4}$

 $\frac{11}{8}-(\frac{5}{16}\times\frac{6}{5}+\frac{2}{7})$

 $=\frac{11}{8}-(\frac{3}{8}+\frac{2}{7})$

 $=\frac{11}{8}-\frac{3}{8}-\frac{2}{7}$

 $=1-\frac{2}{7}$

 $=\frac{5}{7}$

$120 ×\frac {3}{5} ×\frac {2}{3}=48($人$)$

答：科技组有$48$人。

$8 ×(1-\frac{1}{4})-\frac{1}{4}=5 \frac{3}{4} \text { (米) }$

答：$ $还剩$ 5 \frac {3}{4} $米。