1) $$-3 \frac{1}{4} - 16 = -3.25 - 16 = -19.25$$
2) $$-2,84 - 5,49 = -8,33$$
3) $$2 - (-6) - 8 = 2 + 6 - 8 = 0$$
4) $$-2 \frac{1}{15} (-1,7) = -\frac{31}{15} \times (-1,7) = \frac{31 \times 1,7}{15} = \frac{52,7}{15} \approx 3,513$$
5) $$3 \frac{2}{5} - 5 \frac{1}{5} = \frac{17}{5} - \frac{26}{5} = -\frac{9}{5} = -1,8$$