Tính:

a) Mẫu: $3:\frac{4}{5}=\frac{3}{1}:\frac{4}{5}=\frac{3}{1}\times \frac{5}{4}=\frac{15}{4}$

Ta có thể viết gọn như sau:

$3:\frac{4}{5}=\frac{3}{1}\times \frac{5}{4}=\frac{15}{4}$

$6:\frac{1}{4}=$ .................................................................................................................

$7:\frac{2}{3}=$ .................................................................................................................

$8:\frac{4}{5}=$ .................................................................................................................