**Решение:**
1) \(\frac{1}{15} + \frac{2}{15} = \frac{1+2}{15} = \frac{3}{15} = \frac{1}{5}\)
2) \(\frac{13}{16} - \frac{3}{16} = \frac{13-3}{16} = \frac{10}{16} = \frac{5}{8}\)
3) \(6 \frac{7}{12} - 1 \frac{4}{12} = (6-1) + (\frac{7}{12} - \frac{4}{12}) = 5 + \frac{7-4}{12} = 5 + \frac{3}{12} = 5 + \frac{1}{4} = 5 \frac{1}{4}\)
**Ответы:**
1) \(\frac{1}{5}\)
2) \(\frac{5}{8}\)
3) \(5 \frac{1}{4}\)