Сократим дроби:
$$\frac{3}{18} = \frac{3 \div 3}{18 \div 3} = \frac{1}{6}$$
$$\frac{4}{16} = \frac{4 \div 4}{16 \div 4} = \frac{1}{4}$$
$$\frac{18}{54} = \frac{18 \div 18}{54 \div 18} = \frac{1}{3}$$
$$\frac{13n}{52n} = \frac{13n \div 13n}{52n \div 13n} = \frac{1}{4}$$
Ответ: $$\frac{1}{6}$$, $$\frac{1}{4}$$, $$\frac{1}{3}$$, $$\frac{1}{4}$$