Решение:
m - \frac{1}{2}m - 0.3m + 2m = m - \frac{5}{10}m - \frac{3}{10}m + \frac{20}{10}m = \frac{10}{10}m - \frac{5}{10}m - \frac{3}{10}m + \frac{20}{10}m = (\frac{10}{10} - \frac{5}{10} - \frac{3}{10} + \frac{20}{10})m = \frac{22}{10}m = \frac{11}{5}m = 2.2m
Ответ: 2.2m