1. 计算下面各题,能简算的要简算。
$\frac{3}{4}÷\frac{2}{5}+\frac{1}{4}×\frac{5}{2}$
$(\frac{7}{24}-\frac{3}{16})÷\frac{1}{8}$
$\frac{5}{6}÷\frac{9}{13}+\frac{1}{6}÷\frac{9}{13}$
$[1-(\frac{1}{4}+\frac{3}{8})]÷\frac{9}{16}$

(1)
$\;\;\;\;\frac{3}{4} ÷ \frac{2}{5} + \frac{1}{4} × \frac{5}{2}$
$=\frac{3}{4} × \frac{5}{2} + \frac{1}{4} × \frac{5}{2}$
$=\frac{5}{2} × (\frac{3}{4} + \frac{1}{4})$
$=\frac{5}{2} × 1$
$=\frac{5}{2}$
(2)
$\;\;\;\;(\frac{7}{24} - \frac{3}{16}) ÷ \frac{1}{8}$
$=(\frac{7}{24} - \frac{3}{16}) × 8$
$=\frac{7}{24} × 8 - \frac{3}{16} × 8$
$=\frac{7}{3} - \frac{3}{2}$
$=\frac{14}{6} - \frac{9}{6}$
$=\frac{5}{6}$
(3)
$\;\;\;\;\frac{5}{6} ÷ \frac{9}{13} + \frac{1}{6} ÷ \frac{9}{13}$
$=(\frac{5}{6} + \frac{1}{6}) × \frac{13}{9}$
$=1 × \frac{13}{9}$
$=\frac{13}{9}$
(4)
$\;\;\;\;[1 - (\frac{1}{4} + \frac{3}{8})] ÷ \frac{9}{16}$
$=[1 - \frac{5}{8}] × \frac{16}{9}$
$=\frac{3}{8} × \frac{16}{9}$
$=\frac{2}{3}$

2. 一瓶果汁有$\frac{6}{5}$升。
(1)喝去$\frac{1}{3}$,喝去多少升？还剩多少升？
(2)喝去$\frac{1}{3}$升,还剩多少升？
(3)喝去一些后还剩$\frac{1}{3}$,还剩多少升？

(1)
喝去：$\frac{6}{5} × \frac{1}{3} = \frac{2}{5} (升)$
还剩：$\frac{6}{5} - \frac{2}{5} = \frac{4}{5} (升)$
(2)
还剩：$\frac{6}{5} - \frac{1}{3} = \frac{18}{15} - \frac{5}{15} = \frac{13}{15} (升)$
(3)
还剩：$\frac{6}{5} × \frac{1}{3} = \frac{2}{5} (升)$