1. 直接写出得数。(4分)
$8×\frac{3}{28}=$ $2 - \frac{7}{10}=$ $\frac{5}{8} + \frac{7}{8}=$ $7 - \frac{5}{6} + \frac{1}{6}=$
$\frac{9}{7}×\frac{14}{3}=$ $\frac{4}{5} + \frac{3}{4}=$ $\frac{1}{2} - \frac{1}{6}=$ $\frac{1}{3}×\frac{2}{5}×30=$
$8×\frac{3}{28}=$ $2 - \frac{7}{10}=$ $\frac{5}{8} + \frac{7}{8}=$ $7 - \frac{5}{6} + \frac{1}{6}=$
$\frac{9}{7}×\frac{14}{3}=$ $\frac{4}{5} + \frac{3}{4}=$ $\frac{1}{2} - \frac{1}{6}=$ $\frac{1}{3}×\frac{2}{5}×30=$
答案：1. $\frac{6}{7}$ $1\frac{3}{10}$(或$\frac{13}{10}$) $\frac{3}{2}$ $6\frac{1}{3}$(或$\frac{19}{3}$) 6 $\frac{31}{20}$ $\frac{1}{3}$ 4
2. 计算下面各题,能简算的要简算。(12分)
$\frac{2}{3} + \frac{4}{5} - \frac{3}{10}$ $36×\frac{4}{9}×\frac{3}{2}$ $\frac{7}{8} + \frac{2}{5} + \frac{1}{8} + \frac{3}{5}$
$\frac{14}{15}×25×\frac{5}{7}$ $\frac{11}{8} - (\frac{5}{6} + \frac{3}{8}) - \frac{1}{6}$ $\frac{8}{9}×\frac{3}{4}×\frac{3}{5}$
$\frac{2}{3} + \frac{4}{5} - \frac{3}{10}$ $36×\frac{4}{9}×\frac{3}{2}$ $\frac{7}{8} + \frac{2}{5} + \frac{1}{8} + \frac{3}{5}$
$\frac{14}{15}×25×\frac{5}{7}$ $\frac{11}{8} - (\frac{5}{6} + \frac{3}{8}) - \frac{1}{6}$ $\frac{8}{9}×\frac{3}{4}×\frac{3}{5}$
答案：2. $\frac{7}{6}$ 24 2 $\frac{50}{3}$ 0 $\frac{2}{5}$
解析：
$\frac{2}{3} + \frac{4}{5} - \frac{3}{10}$
$=\frac{20}{30} + \frac{24}{30} - \frac{9}{30}$
$=\frac{44}{30} - \frac{9}{30}$
$=\frac{35}{30}$
$=\frac{7}{6}$
$36×\frac{4}{9}×\frac{3}{2}$
$=16×\frac{3}{2}$
$=24$
$\frac{7}{8} + \frac{2}{5} + \frac{1}{8} + \frac{3}{5}$
$=(\frac{7}{8} + \frac{1}{8}) + (\frac{2}{5} + \frac{3}{5})$
$=1 + 1$
$=2$
$\frac{14}{15}×25×\frac{5}{7}$
$=\frac{14}{15}×\frac{5}{7}×25$
$=\frac{2}{3}×25$
$=\frac{50}{3}$
$\frac{11}{8} - (\frac{5}{6} + \frac{3}{8}) - \frac{1}{6}$
$=\frac{11}{8} - \frac{5}{6} - \frac{3}{8} - \frac{1}{6}$
$=(\frac{11}{8} - \frac{3}{8}) - (\frac{5}{6} + \frac{1}{6})$
$=1 - 1$
$=0$
$\frac{8}{9}×\frac{3}{4}×\frac{3}{5}$
$=\frac{2}{3}×\frac{3}{5}$
$=\frac{2}{5}$
$=\frac{20}{30} + \frac{24}{30} - \frac{9}{30}$
$=\frac{44}{30} - \frac{9}{30}$
$=\frac{35}{30}$
$=\frac{7}{6}$
$36×\frac{4}{9}×\frac{3}{2}$
$=16×\frac{3}{2}$
$=24$
$\frac{7}{8} + \frac{2}{5} + \frac{1}{8} + \frac{3}{5}$
$=(\frac{7}{8} + \frac{1}{8}) + (\frac{2}{5} + \frac{3}{5})$
$=1 + 1$
$=2$
$\frac{14}{15}×25×\frac{5}{7}$
$=\frac{14}{15}×\frac{5}{7}×25$
$=\frac{2}{3}×25$
$=\frac{50}{3}$
$\frac{11}{8} - (\frac{5}{6} + \frac{3}{8}) - \frac{1}{6}$
$=\frac{11}{8} - \frac{5}{6} - \frac{3}{8} - \frac{1}{6}$
$=(\frac{11}{8} - \frac{3}{8}) - (\frac{5}{6} + \frac{1}{6})$
$=1 - 1$
$=0$
$\frac{8}{9}×\frac{3}{4}×\frac{3}{5}$
$=\frac{2}{3}×\frac{3}{5}$
$=\frac{2}{5}$
3. 解方程。(6分)
$3.7x + x = 23.5$ $5x - \frac{3}{4} = \frac{1}{4}$ $8x - 16 + 8 = 50$
$3.7x + x = 23.5$ $5x - \frac{3}{4} = \frac{1}{4}$ $8x - 16 + 8 = 50$
答案：3. $x=5$ $x=\frac{1}{5}$ $x=\frac{29}{4}$
解析：
解：$3.7x + x = 23.5$
$4.7x = 23.5$
$x = 23.5 ÷ 4.7$
$x = 5$
$5x - \frac{3}{4} = \frac{1}{4}$
$5x = \frac{1}{4} + \frac{3}{4}$
$5x = 1$
$x = 1 ÷ 5$
$x = \frac{1}{5}$
$8x - 16 + 8 = 50$
$8x - 8 = 50$
$8x = 50 + 8$
$8x = 58$
$x = 58 ÷ 8$
$x = \frac{29}{4}$
$4.7x = 23.5$
$x = 23.5 ÷ 4.7$
$x = 5$
$5x - \frac{3}{4} = \frac{1}{4}$
$5x = \frac{1}{4} + \frac{3}{4}$
$5x = 1$
$x = 1 ÷ 5$
$x = \frac{1}{5}$
$8x - 16 + 8 = 50$
$8x - 8 = 50$
$8x = 50 + 8$
$8x = 58$
$x = 58 ÷ 8$
$x = \frac{29}{4}$
1. $\frac{7}{8} =$ (
14
) $÷ 16 = \frac{(\ )}{24} = \frac{56}{(\ )} =$ (0.875
)(填小数)答案：1. 14 21 64 0.875