其它
$$\frac{4}{9}\div \frac{1}{4}=$$~\uline{~~~~~~~~~~}~． 
Overseas Competition->Knowledge Point->Calculation Modules->Fractions
$$\frac{4}{9}\div \frac{1}{4}=\frac{4}{9}\times \frac{4}{1}=\frac{16}{9}$$ 