[tex]a)( \frac{7}{8} - \frac{1}{8}) + \frac{1}{4} = \frac{6}{8} + \frac{1}{4} = \frac{6}{8} + \frac{2}{8} (am \: amplificat \: cu \: 2) = \frac{8}{8} = 1 \\ \\ b)( \frac{5}{6} + \frac{7}{6} ) - \frac{1}{7} = \frac{12}{6} - \frac{1}{7} = \frac{84}{42} - \frac{6}{42} (am \: amplificat \: cu \: 7 \: si \: 6) = \frac{78}{42} = \frac{13}{7} [/tex]
