Tính
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3) \( \frac{4}{15} - \left( 2,9 - \frac{11}{15} \right) \)
7) \( \left( 3 - \frac{1}{4} - \frac{2}{3} \right) - \left( 5 + \frac{1}{3} - \frac{6}{5} \right) + \left( -6 - \frac{7}{4} - \frac{-1}{5} \right) \)
8) \( \left( 6 - \frac{2}{3} + \frac{1}{2} \right) - \left( 5 - \frac{5}{3} - \frac{3}{2} \right) - \left( 3 - \frac{7}{3} + \frac{5}{2} \right) \)