Laske.

a) [[$2\cdot \dfrac{1}{4}-\dfrac{1}{4}$]] =

b) [[$7- 3 \cdot \dfrac{5}{6} $]] =

c) [[$ (3-2):6$]] =

d) [[$ \dfrac{4}{5} : 6 - \dfrac{1}{20} $]] =