Laske.

a) [[$ 6 \dfrac{3}{4} - 2\dfrac{1}{2} + 3 \dfrac{1}{8} $]] =

b) [[$ -4 \dfrac{5}{6} - 2 \dfrac{3}{4} $]] =

c) [[$ 3 \dfrac{1}{8} - 5 \dfrac{4}{7} $]] =