55. \(-\frac{3}{8} - (-\frac{1}{9})\)

Решение:

\(-\frac{3}{8} - (-\frac{1}{9}) = -\frac{3}{8} + \frac{1}{9} = -\frac{3 \times 9}{8 \times 9} + \frac{1 \times 8}{9 \times 8} = -\frac{27}{72} + \frac{8}{72} = \frac{-27 + 8}{72} = -\frac{19}{72}\)

Ответ: -\(\frac{19}{72}\)