a) $$-3,5-(-1,43) = -3,5 + 1,43 = -2,07$$
б) $$2,6 \cdot 4 \frac{3}{13} = 2,6 \cdot \frac{55}{13} = \frac{26}{10} \cdot \frac{55}{13} = \frac{2}{10} \cdot 55 = \frac{1}{5} \cdot 55 = 11$$
в) $$2 \frac{3}{4}: 10 \frac{1}{6} = \frac{11}{4}: \frac{61}{6} = \frac{11}{4} \cdot \frac{6}{61} = \frac{11}{2} \cdot \frac{3}{61} = \frac{33}{122}$$
Ответ: