let's firstly convert the mixed fractions to improper fractions and then add them up, bearing in mind that the LCD from 12 and 6 will just be 12.
[tex]\bf \stackrel{mixed}{14\frac{11}{12}}\implies \cfrac{14\cdot 12+11}{12}\implies \stackrel{improper}{\cfrac{179}{12}}~\hfill \stackrel{mixed}{3\frac{1}{6}}\implies \cfrac{3\cdot 6+1}{6}\stackrel{improper}{\cfrac{19}{6}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{179}{12}+\cfrac{19}{6}\implies \stackrel{\textit{using the LCD of 12}}{\cfrac{(1)179~~+~~(2)19}{12}}\implies \cfrac{179+38}{12}\implies \cfrac{217}{12}\implies 18\frac{1}{12}[/tex]
