89. Найдите значение выражения: a) 6\frac{3}{4}-2\frac{5}{6}-1\frac{3}{8}. 6)9\frac{8}{15}-4\frac{1}{12}+3\frac{7}{20}; B) 7\frac{5}{8}+3\frac{2}{3}-8\frac{3}{16}; r) 9\frac{23}{25}-4\frac{7}{10}-2\frac{1}{5}; д) 20-(3\frac{1}{6}+2\frac{3}{4}); e) 1\frac{5}{6}+(3-1\frac{7}{10}).

a) $$6\frac{3}{4}-2\frac{5}{6}-1\frac{3}{8} = 6\frac{18}{24}-2\frac{20}{24}-1\frac{9}{24} = 5\frac{42}{24}-2\frac{20}{24}-1\frac{9}{24} = 3\frac{13}{24}$$

Ответ:$$3\frac{13}{24}$$

б) $$9\frac{8}{15}-4\frac{1}{12}+3\frac{7}{20} = 9\frac{32}{60}-4\frac{5}{60}+3\frac{21}{60} = 12\frac{53}{60}-4\frac{5}{60} = 8\frac{48}{60} = 8\frac{4}{5}$$

Ответ:$$8\frac{4}{5}$$

в) $$7\frac{5}{8}+3\frac{2}{3}-8\frac{3}{16} = 7\frac{15}{24}+3\frac{16}{24}-8\frac{3}{16} = 10\frac{31}{24}-8\frac{3}{16} = 11\frac{7}{24}-8\frac{3}{16} = 11\frac{14}{48}-8\frac{9}{48} = 3\frac{5}{48}$$

Ответ:$$3\frac{5}{48}$$

г) $$9\frac{23}{25}-4\frac{7}{10}-2\frac{1}{5} = 9\frac{46}{50}-4\frac{35}{50}-2\frac{10}{50} = 9\frac{46}{50}-6\frac{45}{50} = 3\frac{1}{50}$$

Ответ:$$3\frac{1}{50}$$

д) $$20-(3\frac{1}{6}+2\frac{3}{4}) = 20-(3\frac{2}{12}+2\frac{9}{12}) = 20-5\frac{11}{12} = 19\frac{12}{12}-5\frac{11}{12} = 14\frac{1}{12}$$

Ответ:$$14\frac{1}{12}$$

е) $$1\frac{5}{6}+(3-1\frac{7}{10}) = 1\frac{5}{6}+(3-1\frac{7}{10}) = 1\frac{5}{6}+(2\frac{10}{10}-1\frac{7}{10}) = 1\frac{5}{6}+1\frac{3}{10} = 1\frac{25}{30}+1\frac{9}{30} = 2\frac{34}{30} = 3\frac{4}{30} = 3\frac{2}{15}$$

Ответ:$$3\frac{2}{15}$$