D=1 + 2 - 1 _ _ _ 6 3 12 aider svp :'(

[tex] \frac{1}{6} [/tex] + [tex] \frac{2}{3} [/tex]-[tex] \frac{1}{12} [/tex] =

([tex] \frac{2+8-1}{12} [/tex] =

 [tex] \frac{9}{12} [/tex] =

[tex] \frac{3}{4} [/tex]