Tính. 4/25 : 4/3

a) $\frac{4}{25}:\frac{4}{3}$

b) $\frac{3}{14}:\frac{6}{7}$

c) $\frac{12}{15}:2$

d) $\frac{21}{8}:6$

a) $\frac{4}{25}:\frac{4}{3}$ = $\frac{4}{25}\times \frac{3}{4}$ = $\frac{12}{100}$ = $\frac{3}{25}$

b) $\frac{3}{14}:\frac{6}{7}$ = $\frac{3}{14}\times \frac{7}{6}$ = $\frac{21}{84}$ = $\frac{1}{4}$

c) $\frac{12}{15}:2$ = $\frac{12}{15}\times \frac{1}{2}$ = $\frac{12}{30}$ = $\frac{2}{5}$

d) $\frac{21}{8}:6$ = $\frac{21}{8}\times \frac{1}{6}$ = $\frac{21}{48}=\frac{7}{16}$