78 1365-507-020 1560 38 =+ 59 1= 各-4= 7-1 8 12. 17 +- 18 24 8

Выполним действия с дробями:

1. $$\frac{1}{3} + \frac{5}{8} =$$ $$\frac{1 \cdot 8}{3 \cdot 8} + \frac{5 \cdot 3}{8 \cdot 3} =$$ $$\frac{8}{24} + \frac{15}{24} =$$ $$\frac{8 + 15}{24} = \frac{23}{24}$$
2. $$\frac{4}{5} + \frac{2}{9} =$$ $$\frac{4 \cdot 9}{5 \cdot 9} + \frac{2 \cdot 5}{9 \cdot 5} =$$ $$\frac{36}{45} + \frac{10}{45} =$$ $$\frac{36 + 10}{45} = \frac{46}{45}$$
3. $$\frac{6}{7} - \frac{1}{4} =$$ $$\frac{6 \cdot 4}{7 \cdot 4} - \frac{1 \cdot 7}{4 \cdot 7} =$$ $$\frac{24}{28} - \frac{7}{28} =$$ $$\frac{24 - 7}{28} = \frac{17}{28}$$
4. $$\frac{7}{8} - \frac{1}{12} =$$ $$\frac{7 \cdot 3}{8 \cdot 3} - \frac{1 \cdot 2}{12 \cdot 2} =$$ $$\frac{21}{24} - \frac{2}{24} =$$ $$\frac{21-2}{24} = \frac{19}{24}$$
5. $$\frac{17}{18} + \frac{17}{24} - \frac{5}{8} =$$ $$\frac{17 \cdot 4}{18 \cdot 4} + \frac{17 \cdot 3}{24 \cdot 3} - \frac{5 \cdot 9}{8 \cdot 9} =$$ $$\frac{68}{72} + \frac{51}{72} - \frac{45}{72} =$$ $$\frac{68 + 51 - 45}{72} =$$ $$\frac{119 - 45}{72} = \frac{74}{72} = \frac{37}{36}$$

Ответ: См. решение