Решение:
\[ 5\frac{3}{10} - 2\frac{1}{5} = 5\frac{3}{10} - 2\frac{1 imes 2}{5 imes 2} = 5\frac{3}{10} - 2\frac{2}{10} = (5-2) + (\frac{3}{10} - \frac{2}{10}) = 3 + \frac{3-2}{10} = 3 + \frac{1}{10} = 3\frac{1}{10} \]
Ответ: $$3\frac{1}{10}$$