а) $$\frac{5}{9}$$ = $$\frac{5 \times 5}{9 \times 5}$$ = $$\frac{25}{45}$$
в) $$\frac{9}{20}$$ = $$\frac{9 \times 5}{20 \times 5}$$ = $$\frac{45}{100}$$
Ответ: а) $$\frac{25}{45}$$, в) $$\frac{45}{100}$$