4) 14\frac{5}{24}a - 3\frac{7}{12}a - 5\frac{9}{16}.

4) $$14\frac{5}{24}a - 3\frac{7}{12}a - 5\frac{9}{16}a = (14\frac{5}{24} - 3\frac{7}{12} - 5\frac{9}{16})a = (14 + \frac{5}{24} - 3 - \frac{7}{12} - 5 - \frac{9}{16})a = (6 + \frac{10}{48} - \frac{28}{48} - \frac{27}{48})a = (6 - \frac{18}{48} - \frac{27}{48})a = (6 - \frac{45}{48})a = (6 - \frac{15}{16})a = (5 + \frac{16}{16} - \frac{15}{16})a = 5\frac{1}{16}a$$

Ответ: $$5\frac{1}{16}a$$