63. Упростите выражение: 1) \frac{5}{18}c + \frac{7}{24}c - \frac{11}{36}c;

1) $$\frac{5}{18}c + \frac{7}{24}c - \frac{11}{36}c = \frac{5 \cdot 4}{18 \cdot 4}c + \frac{7 \cdot 3}{24 \cdot 3}c - \frac{11 \cdot 2}{36 \cdot 2}c = \frac{20}{72}c + \frac{21}{72}c - \frac{22}{72}c = \frac{20+21-22}{72}c = \frac{19}{72}c$$

Ответ: $$\frac{19}{72}c$$