Bài giải:

(Tính bằng cách hợp lý nhất:)

$\begin{array}{*{35}{l}}\text{ }\!\!~\!\!\text{ } & 1\frac{1}{3}\times 1\frac{1}{4}\times 1\frac{1}{5}\times 1\frac{1}{6}\times 1\frac{1}{7}\times 1\frac{1}{8}  \\\text{  }\!\!~\!\!\text{ } & =\frac{4}{3}\times \frac{5}{4}\times \frac{6}{5}\times \frac{7}{6}\times \frac{8}{7}\times \frac{9}{8}  \\\text{}\!\!~\!\!\text{ } & =\frac{9}{3}=3  \\\end{array}$