2. Выполнить сложение дробей:
a) $$\frac{4}{15} + \frac{3}{5} = \frac{4}{15} + \frac{3 \cdot 3}{5 \cdot 3} = \frac{4}{15} + \frac{9}{15} = \frac{4 + 9}{15} = \frac{13}{15}$$
Ответ: $$\frac{13}{15}$$
б) $$1 \frac{9}{14} + 2 \frac{1}{7} = 1 \frac{9}{14} + 2 \frac{1 \cdot 2}{7 \cdot 2} = 1 \frac{9}{14} + 2 \frac{2}{14} = (1 + 2) + (\frac{9}{14} + \frac{2}{14}) = 3 + \frac{11}{14} = 3 \frac{11}{14}$$
Ответ: $$3 \frac{11}{14}$$
в) $$1 \frac{8}{9} + 2 \frac{9}{16} = \frac{1 \cdot 9 + 8}{9} + \frac{2 \cdot 16 + 9}{16} = \frac{17}{9} + \frac{41}{16} = \frac{17 \cdot 16}{9 \cdot 16} + \frac{41 \cdot 9}{16 \cdot 9} = \frac{272}{144} + \frac{369}{144} = \frac{272 + 369}{144} = \frac{641}{144} = 4 \frac{65}{144}$$
Ответ: $$4 \frac{65}{144}$$