$\frac{3}{4} × 20 =$
$4 ÷ \frac{2}{5} =$
$\frac{3}{17} × (\frac{1}{4} - 0.25) =$
$\frac{15}{22} ÷ 10 =$
$3.5 ÷ \frac{1}{2} =$
$\frac{2}{9} - \frac{2}{9} ÷ 2 =$
$\frac{3}{5} × \frac{10}{21} =$
$\frac{2}{9} ÷ \frac{2}{3} =$
$(\frac{4}{9} - \frac{1}{3}) × 27 =$
$3.14 × 10^2 =$
$\frac{8}{9} ÷ \frac{5}{3} =$
$\frac{4}{3} × \frac{5}{7} ÷ \frac{4}{3} × \frac{5}{7} =$
$1.5 ÷ 50\% =$
$\frac{4}{15} × \frac{3}{16} =$
$\frac{1}{6} + \frac{5}{6} ÷ 5 =$

1. 15 10 0 $\frac{3}{44}$ 7 $\frac{1}{9}$ $\frac{2}{7}$ $\frac{1}{3}$ 3 314 $\frac{8}{15}$ $\frac{25}{49}$ 3 $\frac{1}{20}$ $\frac{1}{3}$

(1) $\frac{1}{5} ÷ 80\% = 4 ÷ (\quad) = (\quad) ÷ 20 = (\quad)\% = (\quad)$（填小数）
(2) $\frac{3}{5} = 3 ÷ (\quad) = (\quad)$（填小数）$= (\quad)\% = (\quad)$折
(3) $3 ÷ (\quad) = 0.375 = (\quad) ÷ 24 = \frac{(\quad)}{40} = (\quad)\%$

2. (1) 16 5 25 0.25
(2) 5 0.6 60 六
(3) 8 9 15 37.5

3 脱式计算（能简算的要简算）
建议用时4分钟 评价：☆☆☆
$25\% × 3.2 × 12.5\%$
$\frac{2}{9} × \frac{3}{8} + \frac{2}{9} ÷ \frac{8}{5}$
$12 × ( \frac{1}{4} + \frac{1}{6} - \frac{1}{3} )$
$\frac{4}{7} + \frac{3}{7} × ( \frac{1}{2} - \frac{1}{6} )$
$\frac{19}{86} × 57 + 19 × \frac{29}{86}$
$\frac{8}{9} ÷ [ ( \frac{5}{6} + \frac{7}{2} ) × \frac{2}{13} ]$

3. 0.1 $\frac{2}{9}$ 1 $\frac{5}{7}$ 19 $\frac{4}{3}$