1. Вычислите: a) $$4 \frac{5}{17} + \frac{8}{17}$$; б) $$9 \frac{11}{12} - 3 \frac{10}{12}$$; в) $$13 + 12 \frac{11}{12}$$; г) $$21 - 8 \frac{7}{15}$$

1. Вычисления:

1. a) \(4 \frac{5}{17} + \frac{8}{17} = 4 \frac{13}{17}\)

2. б) \(9 \frac{11}{12} - 3 \frac{10}{12} = (9 - 3) + (\frac{11}{12} - \frac{10}{12}) = 6 + \frac{1}{12} = 6 \frac{1}{12}\)

3. в) \(13 + 12 \frac{11}{12} = (13 + 12) + \frac{11}{12} = 25 \frac{11}{12}\)

4. г) \(21 - 8 \frac{7}{15} = 20 \frac{15}{15} - 8 \frac{7}{15} = (20 - 8) + (\frac{15}{15} - \frac{7}{15}) = 12 + \frac{8}{15} = 12 \frac{8}{15}\)

Ответ: a) \(4 \frac{13}{17}\); б) \(6 \frac{1}{12}\); в) \(25 \frac{11}{12}\); г) \(12 \frac{8}{15}\).