1. Раскройте скобки: 1) 54 – (11 – 26); 2) 43 + (28 – 13); 3) – (–5,27 + 2,11); 4) \(\frac{7}{15} + (\frac{8}{15} - \frac{6}{13})\).

Решение:

1. \( 54 - (11 - 26) = 54 - 11 + 26 = 43 + 26 = 69 \)
2. \( 43 + (28 - 13) = 43 + 15 = 58 \)
3. \( - (-5,27 + 2,11) = - (-3,16) = 3,16 \)
4. \( \frac{7}{15} + (\frac{8}{15} - \frac{6}{13}) = \frac{7}{15} + \frac{8}{15} - \frac{6}{13} = \frac{15}{15} - \frac{6}{13} = 1 - \frac{6}{13} = \frac{13}{13} - \frac{6}{13} = \frac{7}{13} \)

Ответ: 1) 69; 2) 58; 3) 3,16; 4) \(\frac{7}{13}\).