4. \frac{(5,6-1\frac{1}{3}) \cdot 1,25}{7 \frac{7}{12}-2,25}.

4. Вычислим значение выражения: $$ \frac{(5,6-1\frac{1}{3}) \cdot 1,25}{7 \frac{7}{12}-2,25} = \frac{(5,6-\frac{4}{3}) \cdot 1,25}{\frac{91}{12}-2,25} = \frac{(\frac{56}{10}-\frac{4}{3}) \cdot \frac{125}{100}}{\frac{91}{12}-\frac{225}{100}} = \frac{(\frac{28}{5}-\frac{4}{3}) \cdot \frac{5}{4}}{\frac{91}{12}-\frac{9}{4}} = \frac{(\frac{28 \cdot 3 - 4 \cdot 5}{15}) \cdot \frac{5}{4}}{\frac{91 - 9 \cdot 3}{12}} = \frac{\frac{84-20}{15} \cdot \frac{5}{4}}{\frac{91-27}{12}} = \frac{\frac{64}{15} \cdot \frac{5}{4}}{\frac{64}{12}} = \frac{\frac{16}{3}}{\frac{16}{3} \cdot \frac{4}{4}} = \frac{\frac{16}{3}}{\frac{16}{3}} = 1$$.

Ответ: 1