1.a) 5/8 + 7/8; 2.a) 2/12 + 7/4; 3.a) 7/30 + 7/3; 4.a) 7/4 + 3/4; 5.a) 1 5/36 + 7/9; 6.a) 2 2/5 + 1 6/10; 7.a) 2 3/20 + 1 5/6; 8.a) 2 5/8 + 3 4/9 + 1 1/7

Решение:

1. \( \frac{5}{8} + \frac{7}{8} = \frac{12}{8} = 1 \frac{4}{8} = 1 \frac{1}{2} \)
2. \( \frac{2}{12} + \frac{7}{4} = \frac{1}{6} + \frac{7}{4} = \frac{2}{12} + \frac{21}{12} = \frac{23}{12} = 1 \frac{11}{12} \)
3. \( \frac{7}{30} + \frac{7}{3} = \frac{7}{30} + \frac{70}{30} = \frac{77}{30} = 2 \frac{17}{30} \)
4. \( \frac{7}{4} + \frac{3}{4} = \frac{10}{4} = 2 \frac{2}{4} = 2 \frac{1}{2} \)
5. \( 1 \frac{5}{36} + \frac{7}{9} = 1 \frac{5}{36} + \frac{28}{36} = 1 \frac{33}{36} = 1 \frac{11}{12} \)
6. \( 2 \frac{2}{5} + 1 \frac{6}{10} = 2 \frac{4}{10} + 1 \frac{6}{10} = 3 \frac{10}{10} = 4 \)
7. \( 2 \frac{3}{20} + 1 \frac{5}{6} = 2 \frac{9}{60} + 1 \frac{50}{60} = 3 \frac{59}{60} \)
8. \( 2 \frac{5}{8} + 3 \frac{4}{9} + 1 \frac{1}{7} = 2 \frac{315}{504} + 3 \frac{224}{504} + 1 \frac{72}{504} = 6 \frac{611}{504} = 7 \frac{107}{504} \)

Ответ: 1. 1 1/2; 2. 1 11/12; 3. 2 17/30; 4. 2 1/2; 5. 1 11/12; 6. 4; 7. 3 59/60; 8. 7 107/504.