1. 填一填。

$\begin{array}{r} \frac {5}{6}\\ \frac {4}{9}\\ \frac {7}{8}\end{array} ×\frac {3}{8}→\begin{array}{r} □ \\ □ \\ □ \end{array}$ $\begin{array}{r} \frac {3}{5}\\ \frac {8}{15}\\ \frac {5}{9}\end{array} ×\frac {5}{9}→\begin{array}{r} □ \\ □ \\ □ \end{array}$

$\begin{array}{r} \frac {5}{16}\\ \frac {1}{6}\\ \frac {21}{64}\end{array}$，$\begin{array}{r} \frac {1}{3}\\ \frac {8}{27}\\ \frac {25}{81}\end{array}$

$\frac{5}{6}×\frac{3}{8}=\frac{5×3}{6×8}=\frac{15}{48}=\frac{5}{16}$
$\frac{4}{9}×\frac{3}{8}=\frac{4×3}{9×8}=\frac{12}{72}=\frac{1}{6}$
$\frac{7}{8}×\frac{3}{8}=\frac{7×3}{8×8}=\frac{21}{64}$
$\frac{3}{5}×\frac{5}{9}=\frac{3×5}{5×9}=\frac{15}{45}=\frac{1}{3}$
$\frac{8}{15}×\frac{5}{9}=\frac{8×5}{15×9}=\frac{40}{135}=\frac{8}{27}$
$\frac{5}{9}×\frac{5}{9}=\frac{5×5}{9×9}=\frac{25}{81}$
最终

2. 在$◯$里填上“＞”“＜”或“=”。
$\frac {7}{8}×\frac {2}{3}◯ \frac {7}{8}×\frac {4}{5}$
$\frac {4}{5}×\frac {3}{2}◯ \frac {4}{5}$
$\frac {3}{8}×\frac {6}{6}◯ \frac {3}{8}$
$\frac {5}{6}×\frac {3}{4}◯ \frac {5}{6}×\frac {4}{3}$
$\frac {8}{9}×\frac {3}{8}◯ \frac {8}{9}×\frac {5}{8}$
$\frac {3}{5}×\frac {5}{8}◯ \frac {3}{8}×\frac {2}{5}$

$\frac{2}{3}=\frac{10}{15}$，$\frac{4}{5}=\frac{12}{15}$，$\frac{10}{15}＜\frac{12}{15}$，即$\frac{2}{3}＜\frac{4}{5}$，所以$\frac {7}{8}×\frac {2}{3}＜ \frac {7}{8}×\frac {4}{5}$
$\frac{3}{2}＞1$，所以$\frac {4}{5}×\frac {3}{2}＞ \frac {4}{5}$
$\frac{6}{6}=1$，所以$\frac {3}{8}×\frac {6}{6}= \frac {3}{8}$
$\frac{3}{4}＜1$，$\frac{4}{3}＞1$，则$\frac{5}{6}×\frac{3}{4}＜\frac{5}{6}$，$\frac{5}{6}×\frac{4}{3}＞\frac{5}{6}$，故$\frac {5}{6}×\frac {3}{4}＜ \frac {5}{6}×\frac {4}{3}$
$\frac{3}{8}＜\frac{5}{8}$，所以$\frac {8}{9}×\frac {3}{8}＜ \frac {8}{9}×\frac {5}{8}$
$\frac{3}{5}×\frac{5}{8}=\frac{3}{8}$，$\frac{3}{8}×\frac{2}{5}=\frac{3}{20}$，$\frac{3}{8}＞\frac{3}{20}$，所以$\frac {3}{5}×\frac {5}{8}＞ \frac {3}{8}×\frac {2}{5}$

3. 一个长方形的长是$\frac{3}{4}$m,宽是长的$\frac{2}{3}$。这个长方形的宽是多少米?面积是多少平方米?

$\frac{3}{4}×\frac{2}{3}=\frac{1}{2}$（米）
$\frac{3}{4}×\frac{1}{2}=\frac{3}{8}$（平方米）
答：这个长方形的宽是$\frac{1}{2}$米，面积是$\frac{3}{8}$平方米。

4. 水果批发市场运来一批西瓜,平均分给甲、乙两个水果店。甲、乙两个水果店第一天分别卖出了这批西瓜的几分之几?

$\frac{1}{2}×\frac{3}{4}=\frac{3}{8}$
$\frac{1}{2}×\frac{2}{3}=\frac{1}{3}$
答：甲水果店第一天卖出了这批西瓜的$\frac{3}{8}$，乙水果店第一天卖出了这批西瓜的$\frac{1}{3}$。