Найдите значение выражения, используя законы сложения: 3/7 + 7 + 4/7 12/25 + 9/10 + 12/25 + 11/10 7/16 + 11/12 + 2 + 13/12 + 25/16 2/9 + 1/8 + 2/9 + 7/8 + 4/9 3/9 + 11 + 2/9 + 3 14/15 + 5/18 + 21/15 + 31/18 + 3 7/11 + 4 + 2/13 + 4/13 + 15/11 1/9 + 5/7 + 2/9 + 1/7 + 6/9

Выполняю задание.

1. $$\frac{3}{7} + 7 + \frac{4}{7} = 7 + (\frac{3}{7} + \frac{4}{7}) = 7 + \frac{7}{7} = 7 + 1 = 8$$

   Ответ: 8

2. $$\frac{12}{25} + \frac{9}{10} + \frac{12}{25} + \frac{11}{10} = (\frac{12}{25} + \frac{12}{25}) + (\frac{9}{10} + \frac{11}{10}) = \frac{24}{25} + \frac{20}{10} = \frac{24}{25} + 2 = 2 \frac{24}{25}$$

   Ответ: $$2 \frac{24}{25}$$

3. $$\frac{7}{16} + \frac{11}{12} + 2 + \frac{13}{12} + \frac{25}{16} = (\frac{7}{16} + \frac{25}{16}) + (\frac{11}{12} + \frac{13}{12}) + 2 = \frac{32}{16} + \frac{24}{12} + 2 = 2 + 2 + 2 = 6$$

   Ответ: 6

4. $$\frac{2}{9} + \frac{1}{8} + \frac{2}{9} + \frac{7}{8} + \frac{4}{9} = (\frac{2}{9} + \frac{2}{9} + \frac{4}{9}) + (\frac{1}{8} + \frac{7}{8}) = \frac{8}{9} + \frac{8}{8} = \frac{8}{9} + 1 = 1 \frac{8}{9}$$

   Ответ: $$1 \frac{8}{9}$$

5. $$\frac{3}{9} + 11 + \frac{2}{9} + 3 = 11 + 3 + (\frac{3}{9} + \frac{2}{9}) = 14 + \frac{5}{9} = 14 \frac{5}{9}$$

   Ответ: $$14 \frac{5}{9}$$

6. $$\frac{14}{15} + \frac{5}{18} + \frac{21}{15} + \frac{31}{18} + 3 = (\frac{14}{15} + \frac{21}{15}) + (\frac{5}{18} + \frac{31}{18}) + 3 = \frac{35}{15} + \frac{36}{18} + 3 = \frac{7}{3} + 2 + 3 = 2 \frac{1}{3} + 5 = 7 \frac{1}{3}$$

   Ответ: $$7 \frac{1}{3}$$

7. $$\frac{7}{11} + 4 + \frac{2}{13} + \frac{4}{13} + \frac{15}{11} = (\frac{7}{11} + \frac{15}{11}) + (\frac{2}{13} + \frac{4}{13}) + 4 = \frac{22}{11} + \frac{6}{13} + 4 = 2 + \frac{6}{13} + 4 = 6 \frac{6}{13}$$

   Ответ: $$6 \frac{6}{13}$$

8. $$\frac{1}{9} + \frac{5}{7} + \frac{2}{9} + \frac{1}{7} + \frac{6}{9} = (\frac{1}{9} + \frac{2}{9} + \frac{6}{9}) + (\frac{5}{7} + \frac{1}{7}) = \frac{9}{9} + \frac{6}{7} = 1 + \frac{6}{7} = 1 \frac{6}{7}$$

   Ответ: $$1 \frac{6}{7}$$