一 计算题。（共51分）

1. 直接写出得数。（7分）
$a - 0.47a =$ $4.5b + 3.6b =$
$8.8x + x =$ $9.3y + 7y =$
$7x + 5x - 10x =$ $6.4y - 4.7y + 1.3y =$
$\frac{7}{9} - \frac{2}{9} =$ $\frac{4}{11} + \frac{11}{4} =$
$1 - \frac{5}{8} =$ $\frac{1}{3} + \frac{1}{9} =$
$\frac{3}{5} - \frac{1}{2} =$ $\frac{4}{5} + \frac{3}{4} =$
$\frac{1}{2} + \frac{5}{8} =$ $1 - \frac{2}{7} =$

$0.53a$ $8.1b$ $9.8x$ $16.3y$ $2x$ $3y$
$\frac{5}{9}$ $1$ $\frac{3}{8}$ $\frac{4}{9}$ $\frac{1}{10}$ $\frac{31}{20}$ $\frac{9}{8}$ $\frac{5}{7}$

2. 计算下面各题，能简算的要简算。（20分）
$\frac{11}{15} - (\frac{1}{6} + \frac{8}{15})$ $\frac{8}{9} - \frac{1}{6} + \frac{2}{3}$
$\frac{13}{9} - (\frac{2}{5} + \frac{4}{9})$ $\frac{7}{8} + \frac{7}{12} + \frac{1}{8}$
$\frac{3}{4} - \frac{1}{6} + \frac{1}{3}$ $\frac{7}{9} - (\frac{4}{7} - \frac{2}{9})$
$\frac{5}{3} - \frac{2}{7} - \frac{5}{7}$ $\frac{7}{5} - (\frac{7}{9} + \frac{2}{5}) + \frac{7}{9}$
$\frac{1}{4} + \frac{1}{8} + \frac{1}{16} + \frac{1}{32} + \frac{1}{64} + \frac{1}{128} + \frac{1}{256}$
$999\frac{8}{9} + 99\frac{8}{9} + 9\frac{8}{9} + \frac{1}{3}$

$\frac{1}{30}$ $\frac{25}{18}$ $\frac{3}{5}$ $1\frac{7}{12}$ $\frac{11}{12}$ $\frac{3}{7}$ $\frac{2}{3}$ $1$ $\frac{127}{256}$ $1110$

3. 解方程。（12分）
$6×7 + 2x = 92$ $3.2x - 2x = 18$
$4.5x + 0.5x = 10.8$ $4x - 6×3 = 32$
$\frac{2}{9} + x = \frac{17}{18}$ $x - \frac{1}{3} = \frac{1}{4}$

$x = 25$ $x = 15$ $x = 2.16$ $x = 12.5$ $x=\frac{13}{18}$ $x=\frac{7}{12}$