Giải câu 7 trang 62 sách toán VNEN lớp 4 tập 2.
$\frac{1}{3}\times \frac{1}{6}\times \frac{1}{9}=\frac{1\times 1\times 1}{3\times 6\times 9}=\frac{1}{162}$
$\frac{1}{3}\times \frac{1}{6}: \frac{1}{9}=\frac{1}{3}\times \frac{1}{6}\times \frac{9}{1}=\frac{1\times 1\times 9}{3\times 6\times 1}=\frac{9}{18}$
$\frac{1}{3}: \frac{1}{6}\times \frac{1}{9}=\frac{1}{3}: \frac{1}{54}=\frac{1}{3}\times \frac{54}{1}=\frac{54}{3}$