1. 直接写出得数。(4分)
$\frac{3}{10} + \frac{3}{10} =$ $14 × \frac{2}{7} =$ $\frac{7}{36} - \frac{1}{12} =$ $1 - \frac{3}{7} + \frac{4}{7} =$
$\frac{5}{8} × \frac{3}{5} =$ $4 - \frac{3}{4} =$ $0.3 + \frac{2}{5} =$ $0 × \frac{1}{5} × \frac{2}{5} =$
$\frac{3}{10} + \frac{3}{10} =$ $14 × \frac{2}{7} =$ $\frac{7}{36} - \frac{1}{12} =$ $1 - \frac{3}{7} + \frac{4}{7} =$
$\frac{5}{8} × \frac{3}{5} =$ $4 - \frac{3}{4} =$ $0.3 + \frac{2}{5} =$ $0 × \frac{1}{5} × \frac{2}{5} =$
答案：1. $\frac{3}{5}$ 4 $\frac{1}{9}$ $\frac{8}{7}$(或 $1\frac{1}{7}$) $\frac{3}{8}$ $3\frac{1}{4}$(或 $\frac{13}{4}$) $\frac{7}{10}$ 0
解析：
$\frac{3}{5}$；4；$\frac{1}{9}$；$\frac{8}{7}$；$\frac{3}{8}$；$\frac{13}{4}$；$\frac{7}{10}$；0
2. 计算下面各题,能简算的要简算。(12分)
$\frac{3}{4} - (\frac{5}{6} - \frac{1}{8})$ $90 × \frac{7}{3} × \frac{1}{21}$ $\frac{6}{7} × \frac{3}{2} × \frac{5}{9}$
$3 - \frac{6}{11} - \frac{7}{11} - \frac{9}{11}$ $\frac{23}{24} × \frac{8}{69} × \frac{1}{2}$ $\frac{2}{7} + [\frac{4}{5} - (\frac{2}{3} - \frac{1}{6})]$
$\frac{3}{4} - (\frac{5}{6} - \frac{1}{8})$ $90 × \frac{7}{3} × \frac{1}{21}$ $\frac{6}{7} × \frac{3}{2} × \frac{5}{9}$
$3 - \frac{6}{11} - \frac{7}{11} - \frac{9}{11}$ $\frac{23}{24} × \frac{8}{69} × \frac{1}{2}$ $\frac{2}{7} + [\frac{4}{5} - (\frac{2}{3} - \frac{1}{6})]$
答案：2. $\frac{1}{24}$ 10 $\frac{5}{7}$ 1 $\frac{1}{18}$ $\frac{41}{70}$
解析：
$\frac{3}{4} - (\frac{5}{6} - \frac{1}{8})$
$=\frac{3}{4} - \frac{5}{6} + \frac{1}{8}$
$=\frac{18}{24} - \frac{20}{24} + \frac{3}{24}$
$=\frac{1}{24}$
$90 × \frac{7}{3} × \frac{1}{21}$
$=90×(\frac{7}{3}×\frac{1}{21})$
$=90×\frac{1}{9}$
$=10$
$\frac{6}{7} × \frac{3}{2} × \frac{5}{9}$
$=\frac{6×3×5}{7×2×9}$
$=\frac{90}{126}$
$=\frac{5}{7}$
$3 - \frac{6}{11} - \frac{7}{11} - \frac{9}{11}$
$=3 - (\frac{6}{11} + \frac{7}{11} + \frac{9}{11})$
$=3 - \frac{22}{11}$
$=3 - 2$
$=1$
$\frac{23}{24} × \frac{8}{69} × \frac{1}{2}$
$=\frac{23×8×1}{24×69×2}$
$=\frac{184}{3312}$
$=\frac{1}{18}$
$\frac{2}{7} + [\frac{4}{5} - (\frac{2}{3} - \frac{1}{6})]$
$=\frac{2}{7} + [\frac{4}{5} - \frac{1}{2}]$
$=\frac{2}{7} + \frac{3}{10}$
$=\frac{20}{70} + \frac{21}{70}$
$=\frac{41}{70}$
$=\frac{3}{4} - \frac{5}{6} + \frac{1}{8}$
$=\frac{18}{24} - \frac{20}{24} + \frac{3}{24}$
$=\frac{1}{24}$
$90 × \frac{7}{3} × \frac{1}{21}$
$=90×(\frac{7}{3}×\frac{1}{21})$
$=90×\frac{1}{9}$
$=10$
$\frac{6}{7} × \frac{3}{2} × \frac{5}{9}$
$=\frac{6×3×5}{7×2×9}$
$=\frac{90}{126}$
$=\frac{5}{7}$
$3 - \frac{6}{11} - \frac{7}{11} - \frac{9}{11}$
$=3 - (\frac{6}{11} + \frac{7}{11} + \frac{9}{11})$
$=3 - \frac{22}{11}$
$=3 - 2$
$=1$
$\frac{23}{24} × \frac{8}{69} × \frac{1}{2}$
$=\frac{23×8×1}{24×69×2}$
$=\frac{184}{3312}$
$=\frac{1}{18}$
$\frac{2}{7} + [\frac{4}{5} - (\frac{2}{3} - \frac{1}{6})]$
$=\frac{2}{7} + [\frac{4}{5} - \frac{1}{2}]$
$=\frac{2}{7} + \frac{3}{10}$
$=\frac{20}{70} + \frac{21}{70}$
$=\frac{41}{70}$
3. 解方程。(8分)
$5.2x - 4.8x = 10$ $5x - 1 + 2 = 65$ $3x + 5 × 1.7 = 10$ $0.4x - \frac{5}{8} = \frac{3}{8}$
$5.2x - 4.8x = 10$ $5x - 1 + 2 = 65$ $3x + 5 × 1.7 = 10$ $0.4x - \frac{5}{8} = \frac{3}{8}$
答案：3. $x = 25$ $x = 12.8$ $x = 0.5$ $x = 2.5$
解析：
解：$5.2x - 4.8x = 10$
$0.4x = 10$
$x = 25$
解：$5x - 1 + 2 = 65$
$5x + 1 = 65$
$5x = 64$
$x = 12.8$
解：$3x + 5 × 1.7 = 10$
$3x + 8.5 = 10$
$3x = 1.5$
$x = 0.5$
解：$0.4x - \frac{5}{8} = \frac{3}{8}$
$0.4x = \frac{3}{8} + \frac{5}{8}$
$0.4x = 1$
$x = 2.5$
$0.4x = 10$
$x = 25$
解：$5x - 1 + 2 = 65$
$5x + 1 = 65$
$5x = 64$
$x = 12.8$
解：$3x + 5 × 1.7 = 10$
$3x + 8.5 = 10$
$3x = 1.5$
$x = 0.5$
解：$0.4x - \frac{5}{8} = \frac{3}{8}$
$0.4x = \frac{3}{8} + \frac{5}{8}$
$0.4x = 1$
$x = 2.5$