7 3 12 20

5) $$\frac{7}{12} + \frac{3}{20} = \frac{7 \cdot 5}{12 \cdot 5} + \frac{3 \cdot 3}{20 \cdot 3} = \frac{35}{60} + \frac{9}{60} = \frac{35+9}{60} = \frac{44}{60} = \frac{11}{15}$$

Ответ: $$\frac{11}{15}$$