11) 4 3/4+(-4 11/12);

11) $$4 \frac{3}{4} + (-4 \frac{11}{12}) = 4 \frac{3}{4} - 4 \frac{11}{12} = \frac{19}{4} - \frac{59}{12} = \frac{19 \cdot 3}{4 \cdot 3} - \frac{59}{12} = \frac{57}{12} - \frac{59}{12} = \frac{57 - 59}{12} = -\frac{2}{12} = -\frac{1}{6}$$

Ответ: $$\frac{-1}{6}$$