一、口算。(每题1分,共15分)
$1.4×\frac {1}{2}=$ $900÷90\% =$ $1\% ×0.1=$
$4.8×40\% =$ $1.05-5\% =$ $0.9÷3.6=$
$125\% ×\frac {12}{5}=$ $28÷\frac {14}{3}=$ $\frac {5}{6}×\frac {7}{8}=$
$\frac {4}{5}+\frac {1}{2}=$ $\frac {12}{13}×\frac {1}{6}=$ $\frac {2}{3}÷150\% =$
$\frac {8}{9}÷\frac {16}{27}=$ $\frac {5}{6}-\frac {2}{3}=$ $\frac {2}{9}×75\% =$

1.0.7 2.1000 3.0.001 4.1.92 5.1 6.0.25 7.3 8.6 9.$\frac{35}{48}$ 10.$\frac{13}{10}$ 11.$\frac{2}{13}$ 12.$\frac{4}{9}$ 13.$\frac{3}{2}$ 14.$\frac{1}{6}$ 15.$\frac{1}{6}$

1. $1.4×\frac{1}{2}=0.7$
2. $900÷90\% = 1000$
3. $1\%×0.1 = 0.001$
4. $4.8×40\% = 1.92$
5. $1.05 - 5\% = 1$
6. $0.9÷3.6 = 0.25$
7. $125\%×\frac{12}{5}=3$
8. $28÷\frac{14}{3}=6$
9. $\frac{5}{6}×\frac{7}{8}=\frac{35}{48}$
10. $\frac{4}{5}+\frac{1}{2}=\frac{13}{10}$
11. $\frac{12}{13}×\frac{1}{6}=\frac{2}{13}$
12. $\frac{2}{3}÷150\%=\frac{4}{9}$
13. $\frac{8}{9}÷\frac{16}{27}=\frac{3}{2}$
14. $\frac{5}{6}-\frac{2}{3}=\frac{1}{6}$
15. $\frac{2}{9}×75\%=\frac{1}{6}$

二、先化简下面各比,再求比值。(每题4分,共24分)
$\frac {4}{9}:\frac {5}{6}$ $2.8:2.1$ $1.5:\frac {2}{3}$
$50\% :\frac {1}{3}$ 4米：60厘米 0.85吨：170千克

1.8:15 $\frac{8}{15}$ 2.4:3 $\frac{4}{3}$ 3.9:4 $\frac{9}{4}$ 4.3:2 $\frac{3}{2}$ 5.20:3 $\frac{20}{3}$ 6.5:1 5

1. $\frac{4}{9}:\frac{5}{6}$
解：$(\frac{4}{9}×18):(\frac{5}{6}×18)=8:15$
比值：$\frac{8}{15}$
2. $2.8:2.1$
解：$(2.8×10):(2.1×10)=28:21=4:3$
比值：$\frac{4}{3}$
3. $1.5:\frac{2}{3}$
解：$\frac{3}{2}:\frac{2}{3}=(\frac{3}{2}×6):(\frac{2}{3}×6)=9:4$
比值：$\frac{9}{4}$
4. $50\%:\frac{1}{3}$
解：$\frac{1}{2}:\frac{1}{3}=(\frac{1}{2}×6):(\frac{1}{3}×6)=3:2$
比值：$\frac{3}{2}$
5. 4米：60厘米
解：400厘米：60厘米$=(400÷20):(60÷20)=20:3$
比值：$\frac{20}{3}$
6. 0.85吨：170千克
解：850千克：170千克$=(850÷170):(170÷170)=5:1$
比值：5

三、解方程。(每题4分,共24分)
$\frac {4}{7}x= \frac {1}{3}×1.2$ $(x-\frac {1}{2})÷4= 0.25$ $x-\frac {2}{3}x+\frac {1}{3}= 2$
$4x-6×\frac {2}{3}= 2$ $\frac {1}{2}(x-3)= 1.5$ $\frac {3}{4}x-50\% = 17.5$

1.$x = 0.7$ 2.$x = 1\frac{1}{2}$ 3.$x = 5$ 4.$x = \frac{3}{2}$ 5.$x = 6$ 6.$x = 24$

1. 解：$\frac{4}{7}x = \frac{1}{3}×1.2$
$\frac{4}{7}x = 0.4$
$x = 0.4×\frac{7}{4}$
$x = 0.7$
2. 解：$(x - \frac{1}{2})÷4 = 0.25$
$x - \frac{1}{2} = 0.25×4$
$x - \frac{1}{2} = 1$
$x = 1 + \frac{1}{2}$
$x = 1\frac{1}{2}$
3. 解：$x - \frac{2}{3}x + \frac{1}{3} = 2$
$\frac{1}{3}x + \frac{1}{3} = 2$
$\frac{1}{3}x = 2 - \frac{1}{3}$
$\frac{1}{3}x = \frac{5}{3}$
$x = 5$
4. 解：$4x - 6×\frac{2}{3} = 2$
$4x - 4 = 2$
$4x = 6$
$x = \frac{3}{2}$
5. 解：$\frac{1}{2}(x - 3) = 1.5$
$x - 3 = 1.5×2$
$x - 3 = 3$
$x = 6$
6. 解：$\frac{3}{4}x - 50\% = 17.5$
$\frac{3}{4}x - 0.5 = 17.5$
$\frac{3}{4}x = 18$
$x = 18×\frac{4}{3}$
$x = 24$