Вычислите: а) \(7\frac{13}{20}+8\frac{7}{20}\); б) \(2\frac{18}{25}+7\frac{8}{25}\); в) \(8\frac{7}{15}-3\frac{11}{15}\).

1. \(7\frac{13}{20}+8\frac{7}{20}=15\frac{20}{20}=16\).
2. \(2\frac{18}{25}+7\frac{8}{25}=9\frac{26}{25}=10\frac{1}{25}\).
3. \(8\frac{7}{15}-3\frac{11}{15}=7\frac{22}{15}-3\frac{11}{15}=4\frac{11}{15}\).

Ответ: а) 16; б) \(10\frac{1}{25}\); в) \(4\frac{11}{15}\).