一、口算。（每题1分，共24分）
9.2÷2.3=
0.63+0.37=
2.75+2.75×9=
0.125×64=
8.2-2.55=
6÷(0.5×4)=
96÷320=
3.2×0.4=
20-3.7-7.3=
2.63+0.37=
20-0.94=
6.9-3.09+3.1=
48÷0.3=
16×2.5=
1.25×2.3×0.8=
$\frac{2}{3}+\frac{3}{2}=$
$\frac{3}{4}+\frac{1}{6}=$
$\frac{2}{3}+\frac{4}{5}+\frac{1}{3}=$
$2-\frac{2}{3}=$
$\frac{5}{13}+\frac{23}{65}=$
$1-\frac{4}{9}+\frac{5}{9}=$
$\frac{4}{5}-\frac{4}{7}=$
$\frac{7}{5}-\frac{1}{4}=$
$\frac{19}{18}-\frac{4}{5}-\frac{1}{5}=$

4 1 27.5 8 5.65 3 0.3 1.28 9 3 19.06 6.91 160 40 2.3 $\dfrac{13}{6}$ $\dfrac{11}{12}$ $1\dfrac{4}{5}$ $1\dfrac{1}{3}$ $\dfrac{48}{65}$ $\dfrac{10}{9}$ $\dfrac{8}{35}$ $\dfrac{23}{20}$ $\dfrac{1}{18}$

二、解方程。（每题3分，共27分）
4.6×2+x=12.8
3.4x+0.3x=14.8
6x-4.2×3=1.98
0.04x÷1.6=2.8
(x+2.5)×8=36
8x+2.4-4.6=5.2
$2x-\frac{4}{7}=\frac{3}{7}$
$\frac{3}{10}+\frac{5}{8}-x=\frac{1}{4}$
$x-\frac{2}{3}+\frac{1}{8}=\frac{1}{6}$

$x = 3.6$ $x = 4$ $x = 2.43$ $x = 112$ $x = 2$ $x = 0.925$ $x = \dfrac{1}{2}$ $x = \dfrac{27}{40}$ $x = \dfrac{17}{24}$

解：4.6×2+x=12.8
9.2+x=12.8
x=12.8-9.2
x=3.6
解：3.4x+0.3x=14.8
3.7x=14.8
x=14.8÷3.7
x=4
解：6x-4.2×3=1.98
6x-12.6=1.98
6x=1.98+12.6
6x=14.58
x=14.58÷6
x=2.43
解：0.04x÷1.6=2.8
0.04x=2.8×1.6
0.04x=4.48
x=4.48÷0.04
x=112
解：(x+2.5)×8=36
x+2.5=36÷8
x+2.5=4.5
x=4.5-2.5
x=2
解：8x+2.4-4.6=5.2
8x-2.2=5.2
8x=5.2+2.2
8x=7.4
x=7.4÷8
x=0.925
解：$2x-\frac{4}{7}=\frac{3}{7}$
$2x=\frac{3}{7}+\frac{4}{7}$
$2x=1$
$x=\frac{1}{2}$
解：$\frac{3}{10}+\frac{5}{8}-x=\frac{1}{4}$
$\frac{12}{40}+\frac{25}{40}-x=\frac{10}{40}$
$\frac{37}{40}-x=\frac{10}{40}$
$x=\frac{37}{40}-\frac{10}{40}$
$x=\frac{27}{40}$
解：$x-\frac{2}{3}+\frac{1}{8}=\frac{1}{6}$
$x=\frac{1}{6}+\frac{2}{3}-\frac{1}{8}$
$x=\frac{4}{24}+\frac{16}{24}-\frac{3}{24}$
$x=\frac{17}{24}$