2. 一间教室的长是8 m,宽是长的$\frac{3}{4}$,这间教室的占地面积是多少平方米?

$8 × \frac{3}{4} × 8 = 48(\mathrm{m}^2)$

算一算
$\frac{1}{4} × 6 =$
$\frac{3}{4} × 14 =$
$\frac{1}{6} × 9 =$
$\frac{1}{6} × 10 =$
$\frac{5}{6} × 15 =$
$\frac{1}{8} × 10 =$
$\frac{3}{8} × 12 =$
$\frac{5}{8} × 6 =$
$\frac{7}{8} × 20 =$
$\frac{1}{9} × 6 =$

$\frac{1}{4} × 6 = \frac{1×6}{4} = \frac{6}{4} = \frac{3}{2}$
$\frac{3}{4} × 14 = \frac{3×14}{4} = \frac{42}{4} = \frac{21}{2}$
$\frac{1}{6} × 9 = \frac{1×9}{6} = \frac{9}{6} = \frac{3}{2}$
$\frac{1}{6} × 10 = \frac{1×10}{6} = \frac{10}{6} = \frac{5}{3}$
$\frac{5}{6} × 15 = \frac{5×15}{6} = \frac{75}{6} = \frac{25}{2}$
$\frac{1}{8} × 10 = \frac{1×10}{8} = \frac{10}{8} = \frac{5}{4}$
$\frac{3}{8} × 12 = \frac{3×12}{8} = \frac{36}{8} = \frac{9}{2}$
$\frac{5}{8} × 6 = \frac{5×6}{8} = \frac{30}{8} = \frac{15}{4}$
$\frac{7}{8} × 20 = \frac{7×20}{8} = \frac{140}{8} = \frac{35}{2}$
$\frac{1}{9} × 6 = \frac{1×6}{9} = \frac{6}{9} = \frac{2}{3}$