1. 直接写出得数。
$6÷\frac{2}{3}=$ $\frac{1}{8}×\frac{4}{5}=$ $72×\frac{2}{3}=$
$\frac{13}{20}+\frac{4}{5}=$ $0.75+0.5=$ $\frac{4}{7}÷\frac{1}{2}=$
$0.4÷0.8=$ $\frac{1}{5}÷5=$ $1.6×0.2=$

$6÷\frac{2}{3}=9$
$\frac{1}{8}×\frac{4}{5}=\frac{1}{10}$
$72×\frac{2}{3}=48$
$\frac{13}{20}+\frac{4}{5}=\frac{29}{20}$
$0.75+0.5=1.25$
$\frac{4}{7}÷\frac{1}{2}=\frac{8}{7}$
$0.4÷0.8=0.5$
$\frac{1}{5}÷5=\frac{1}{25}$
$1.6×0.2=0.32$

2. 下面各题,怎样算简便就怎样算。
$2-\frac{3}{8}÷\frac{7}{16}-\frac{1}{7}$
$\frac{3}{4}×(\frac{7}{15}-\frac{1}{5})÷\frac{2}{3}$
$[1-(\frac{3}{4}+\frac{1}{12})]×\frac{3}{2}$
$(13+\frac{1}{9})×\frac{9}{13}$
$12-(2.75+1.25)×2$
$3.8×5.2+3.8×4.8$

$2-\frac{3}{8}÷\frac{7}{16}-\frac{1}{7}$
$=2-\frac{3}{8}×\frac{16}{7}-\frac{1}{7}$
$=2-\frac{6}{7}-\frac{1}{7}$
$=2-(\frac{6}{7}+\frac{1}{7})$
$=2-1$
$=1$
$\frac{3}{4}×(\frac{7}{15}-\frac{1}{5})÷\frac{2}{3}$
$=\frac{3}{4}×(\frac{7}{15}-\frac{3}{15})×\frac{3}{2}$
$=\frac{3}{4}×\frac{4}{15}×\frac{3}{2}$
$=\frac{1}{5}×\frac{3}{2}$
$=\frac{3}{10}$
$[1-(\frac{3}{4}+\frac{1}{12})]×\frac{3}{2}$
$=[1-(\frac{9}{12}+\frac{1}{12})]×\frac{3}{2}$
$=[1-\frac{10}{12}]×\frac{3}{2}$
$=\frac{1}{6}×\frac{3}{2}$
$=\frac{1}{4}$
$(13+\frac{1}{9})×\frac{9}{13}$
$=13×\frac{9}{13}+\frac{1}{9}×\frac{9}{13}$
$=9+\frac{1}{13}$
$=9\frac{1}{13}$
$12-(2.75+1.25)×2$
$=12-4×2$
$=12-8$
$=4$
$3.8×5.2+3.8×4.8$
$=3.8×(5.2+4.8)$
$=3.8×10$
$=38$