Laske.

a) [[$ \dfrac{1}{2} + \dfrac{1}{2} $]] =

b) [[$ \dfrac{3}{5} + \dfrac{1}{5} $]] =

c) [[$ \dfrac{7}{10} - \dfrac{6}{10} $]] =

d) [[$ \dfrac{99}{100} - \dfrac{66}{100} $]] =