一、口算。
$76\% × \frac {1}{4}=$ $0.3×0.15=$ $40÷25\% =$
$40×0.04=$ $0.09+9.1=$ $\frac {13}{14}-\frac {5}{7}=$
$0.3-0.125=$ $6.4÷3.2=$ $\frac {1}{15}÷\frac {3}{5}=$
$\frac {3}{7}×\frac {7}{36}=$ $\frac {2}{3}+\frac {3}{5}=$ $\frac {1}{3}÷\frac {11}{6}=$
$\frac {7}{8}÷\frac {7}{9}=$ $5.61+1.1=$ $3.6×20\% =$
$3600-800=$ $\frac {11}{17}×\frac {1}{22}=$ $4.8+5.6=$
$\frac {2}{3}×15=$ $\frac {2}{3}÷30\% =$ $80\% ÷35\% =$

一、0.19 0.045 160
1.6 9.19 $\dfrac{3}{14}$
0.175 2 $\dfrac{1}{9}$
$\dfrac{1}{12}$ $\dfrac{19}{15}$ $\dfrac{2}{11}$
$\dfrac{9}{8}$ 6.71 0.72
2800 $\dfrac{1}{34}$ 10.4
10 $\dfrac{20}{9}$ $\dfrac{16}{7}$

二、计算下面各题，怎样简便就怎样计算。
$\frac {4}{5}×(\frac {13}{20}-\frac {3}{20})$ $8×\frac {2}{9}+2÷9$ $\frac {9}{20}÷[1.5×(20\% +\frac {4}{5})]$
 
$1.25×32×2.5$ $(\frac {2}{3}+\frac {1}{6}-\frac {4}{9})÷\frac {1}{72}$ $28\% ×52+2.8×4.8$

$1.原式=\frac {4}{5}×\frac {1}{2}=\frac {2}{5}$
$2.原式=\frac {2}{9}×(8+1)=2$
$3.原式=\frac {9}{20}×\frac {2}{3}=\frac {3}{10}$
4.原式=(1.25×8)×(4×2.5)=100
5.原式=48+12-32=28
6.原式=2.8×(5.2+4.8)=28