Tính. 1/6x2/3

a) $\frac{1}{6}\times \frac{2}{3}$

b) $\frac{6}{5}\times \frac{3}{8}$

c) $\frac{4}{3}\times \frac{8}{9}$

d) $\frac{5}{12}\times \frac{12}{5}$

a) $\frac{1}{6}\times \frac{2}{3}=\frac{1\times 2}{6\times 3}$ = $\frac{2}{18}$ = $\frac{1}{9}$

b) $\frac{6}{5}\times \frac{3}{8}$ = $\frac{18}{40}$ = $\frac{2}{5}$

c) $\frac{4}{3}\times \frac{8}{9}=\frac{4\times 8}{3\times 9}$ = $\frac{32}{27}$

d) $\frac{5}{12}\times \frac{12}{5}$ = $\frac{60}{60}$ = 1