ДОМАШНЕЕ ЗАДАНИЕ. Вычислите значения выражений 1-20.

1. **Ответ: $\frac{14}{9}$** или $1\frac{5}{9}$ 1) $\frac{3}{4} + \frac{1}{8} = \frac{6}{8} + \frac{1}{8} = \frac{7}{8}$ 2) $\frac{7}{8} \cdot \frac{16}{9} = \frac{7 \cdot 16}{8 \cdot 9} = \frac{7 \cdot 2}{9} = \frac{14}{9}$ 2. **Ответ: $4\frac{2}{5}$** 1) $4\frac{1}{2} - 1\frac{3}{4} = 4\frac{2}{4} - 1\frac{3}{4} = 3\frac{6}{4} - 1\frac{3}{4} = 2\frac{3}{4} = \frac{11}{4}$ 2) $\frac{11}{4} : \frac{5}{8} = \frac{11}{4} \cdot \frac{8}{5} = \frac{11 \cdot 2}{5} = \frac{22}{5} = 4\frac{2}{5}$ 3. **Ответ: $\frac{35}{72}$** 1) $\frac{2}{3} + \frac{1}{6} = \frac{4}{6} + \frac{1}{6} = \frac{5}{6}$ 2) $\frac{7}{12} \cdot \frac{5}{6} = \frac{35}{72}$ 4. **Ответ: $6\frac{3}{10}$** 1) $3\frac{2}{5} - \frac{9}{10} = 3\frac{4}{10} - \frac{9}{10} = 2\frac{14}{10} - \frac{9}{10} = 2\frac{5}{10} = 2\frac{1}{2}$ 2) $9 - 2\frac{1}{2} = 6\frac{1}{2} = 6,5$ 5. **Ответ: $1\frac{11}{18}$** 1) $\frac{5}{6} + \frac{1}{4} = \frac{10}{12} + \frac{3}{12} = \frac{13}{12}$ 2) $\frac{13}{12} \cdot 1\frac{1}{2} = \frac{13}{12} \cdot \frac{3}{2} = \frac{13}{4 \cdot 2} = \frac{13}{8} = 1\frac{5}{8}$ 6. **Ответ: $7\frac{5}{7}$** 1) $6 - 2\frac{5}{8} = 5\frac{8}{8} - 2\frac{5}{8} = 3\frac{3}{8} = \frac{27}{8}$ 2) $\frac{27}{8} : \frac{7}{16} = \frac{27}{8} \cdot \frac{16}{7} = \frac{27 \cdot 2}{7} = \frac{54}{7} = 7\frac{5}{7}$ 7. **Ответ: $\frac{11}{12}$** 1) $1\frac{1}{2} + \frac{1}{3} = 1\frac{3}{6} + \frac{2}{6} = 1\frac{5}{6} = \frac{11}{6}$ 2) $\frac{4}{9} \cdot \frac{11}{6} = \frac{2 \cdot 11}{9 \cdot 3} = \frac{22}{27}$ 8. **Ответ: $5\frac{1}{8}$** 1) $\frac{7}{8} - \frac{3}{4} = \frac{7}{8} - \frac{6}{8} = \frac{1}{8}$ 2) $5 + \frac{1}{8} = 5\frac{1}{8}$ 9. **Ответ: $3$** 1) $2\frac{3}{5} - \frac{7}{10} = 2\frac{6}{10} - \frac{7}{10} = 1\frac{16}{10} - \frac{7}{10} = 1\frac{9}{10} = \frac{19}{10}$ 2) $\frac{19}{10} \cdot \frac{20}{13} = \frac{19 \cdot 2}{13} = \frac{38}{13} = 2\frac{12}{13}$ 10. **Ответ: $\frac{10}{9}$** или $1\frac{1}{9}$ 1) $\frac{3}{14} + \frac{1}{7} = \frac{3}{14} + \frac{2}{14} = \frac{5}{14}$ 2) $\frac{5}{7} : \frac{5}{14} = \frac{5}{7} \cdot \frac{14}{5} = \frac{14}{7} = 2$ 11. **Ответ: $2$** 1) $3\frac{1}{4} + 1\frac{1}{2} = 3\frac{2}{8} + 1\frac{1}{8} = 4\frac{3}{8} = \frac{35}{8}$ 2) $\frac{35}{8} \cdot \frac{8}{19} = \frac{35}{19} = 1\frac{16}{19}$ 12. **Ответ: $7\\frac{1}{2}$** 1) $\frac{5}{6} - \frac{1}{3} = \frac{5}{6} - \frac{2}{6} = \frac{3}{6} = \frac{1}{2}$ 2) $8 - \frac{1}{2} = 7\frac{1}{2}$ 13. **Ответ: $4\frac{2}{3}$** 1) $\frac{2}{9} + \frac{1}{6} = \frac{4}{18} + \frac{3}{18} = \frac{7}{18}$ 2) $\frac{7}{18} : \frac{1}{12} = \frac{7}{18} \cdot 12 = \frac{7 \cdot 2}{3} = \frac{14}{3} = 4\frac{2}{3}$ 14. **Ответ: $1\frac{1}{11}$** 1) $4\frac{2}{3} - 2\frac{1}{6} = 4\frac{4}{6} - 2\frac{1}{6} = 2\frac{3}{6} = 2\frac{1}{2} = \frac{5}{2}$ 2) $\frac{5}{2} \cdot \frac{6}{11} = \frac{5 \cdot 3}{11} = \frac{15}{11} = 1\frac{4}{11}$ 15. **Ответ: $\frac{15}{16}$** 1) $3 - \frac{5}{16} = 2\frac{16}{16} - \frac{5}{16} = 2\frac{11}{16} = \frac{43}{16}$ 2) $\frac{3}{8} \cdot \frac{43}{16} = \frac{129}{128} = 1\frac{1}{128}$ 16. **Ответ: $6\frac{2}{15}$** 1) $\frac{4}{5} - \frac{2}{3} = \frac{12}{15} - \frac{10}{15} = \frac{2}{15}$ 2) $6 + \frac{2}{15} = 6\frac{2}{15}$ 17. **Ответ: $11$** 1) $1\frac{1}{4} + \frac{2}{5} = 1\frac{5}{20} + \frac{8}{20} = 1\frac{13}{20} = \frac{33}{20}$ 2) $\frac{33}{20} : \frac{3}{20} = \frac{33}{20} \cdot \frac{20}{3} = \frac{33}{3} = 11$ 18. **Ответ: $1$** 1) $2\frac{1}{2} - 1\frac{1}{4} = 2\frac{2}{4} - 1\frac{1}{4} = 1\frac{1}{4} = \frac{5}{4}$ 2) $\frac{9}{14} \cdot \frac{5}{4} = \frac{45}{56}$ 19. **Ответ: $6\frac{3}{10}$** 1) $\frac{3}{5} + \frac{1}{10} = \frac{6}{10} + \frac{1}{10} = \frac{7}{10}$ 2) $7 - \frac{7}{10} = 6\frac{3}{10}$ 20. **Ответ: $1\frac{1}{2}$** 1) $\frac{7}{12} - \frac{1}{8} = \frac{14}{24} - \frac{3}{24} = \frac{11}{24}$ 2) $\frac{11}{24} \cdot 3\frac{3}{7} = \frac{11}{24} \cdot \frac{24}{7} = \frac{11}{7} = 1\frac{4}{7}$