Răspuns:
[tex] - \frac{1}{6} - \frac{3}{6} = \frac{ - 1 - 3}{6} = \frac{ - 4}{6} = - \frac{4}{6} \\ \frac{5}{6} - \frac{7}{8} = \frac{5 \times 4}{6 \times 4} - \frac{7 \times 3}{8 \times 3} = \frac{20}{24} - \frac{21}{24} = \frac{ - 1}{24} = - \frac{1}{24} [/tex]
