3) 10-8

3) Вычислим: $$10\frac{11}{24}-8\frac{19}{36}=\frac{10 \cdot 24 + 11}{24} - \frac{8 \cdot 36 + 19}{36}=\frac{240+11}{24} - \frac{288+19}{36} = \frac{251}{24} - \frac{307}{36} = \frac{251 \cdot 3}{24 \cdot 3} - \frac{307 \cdot 2}{36 \cdot 2} = \frac{753}{72} - \frac{614}{72} = \frac{753 - 614}{72} = \frac{139}{72} = 1\frac{67}{72}$$.

Ответ: $$1\frac{67}{72}$$