Задание 89 Вариант 2 Самостоятельная работа ГДЗ Дидактические материалы Чесноков 6 класс (Математика)

Чтобы сложить или вычесть дроби с разными знаменателями, сначала приводим их к наименьшему общему знаменателю, а затем выполняем действия.

а) $$2\frac{1}{8}+8\frac{1}{12}-5\frac{5}{6}$$

$$2\frac{1}{8}+8\frac{1}{12}-5\frac{5}{6} =2\frac{3}{24}+8\frac{2}{24}-5\frac{20}{24} =10\frac{5}{24}-5\frac{20}{24} =9\frac{29}{24}-5\frac{20}{24} =4\frac{9}{24} =4\frac{3}{8}$$

б) $$3\frac{3}{5}+3\frac{11}{15}-1\frac{1}{12}$$

$$3\frac{3}{5}+3\frac{11}{15}-1\frac{1}{12} =3\frac{9}{15}+3\frac{11}{15}-1\frac{1}{12} =6\frac{20}{15}-1\frac{1}{12} =7\frac{5}{15}-1\frac{1}{12} =7\frac{1}{3}-1\frac{1}{12} =7\frac{4}{12}-1\frac{1}{12} =6\frac{3}{12} =6\frac{1}{4}$$

в) $$4\frac{9}{10}-1\frac{5}{12}-1\frac{11}{24}$$

$$4\frac{9}{10}-1\frac{5}{12}-1\frac{11}{24} =4\frac{9}{10}-\left(1\frac{5}{12}+1\frac{11}{24}\right) =4\frac{9}{10}-\left(1\frac{10}{24}+1\frac{11}{24}\right) =4\frac{9}{10}-2\frac{21}{24} =4\frac{9}{10}-2\frac{7}{8} =4\frac{36}{40}-2\frac{35}{40} =2\frac{1}{40}$$

г) $$12\frac{5}{6}-6\frac{1}{4}-1\frac{1}{3}$$

$$12\frac{5}{6}-6\frac{1}{4}-1\frac{1}{3} =12\frac{10}{12}-6\frac{3}{12}-1\frac{4}{12} =6\frac{12}{12}-1\frac{4}{12} =5\frac{3}{12} =5\frac{1}{4}$$

д) $$8\frac{3}{8}-\left(5\frac{5}{6}+1\frac{3}{4}\right)$$

$$8\frac{3}{8}-\left(5\frac{5}{6}+1\frac{3}{4}\right) =8\frac{3}{8}-\left(5\frac{10}{12}+1\frac{9}{12}\right) =8\frac{3}{8}-6\frac{19}{12} =8\frac{9}{24}-7\frac{14}{24} =7\frac{33}{24}-7\frac{14}{24} =7\frac{19}{24}$$

е) $$11-\left(4\frac{5}{6}+3\frac{3}{10}\right)$$

$$11-\left(4\frac{5}{6}+3\frac{3}{10}\right) =11-\left(4\frac{25}{30}+3\frac{9}{30}\right) =11-7\frac{34}{30} =11-8\frac{4}{30} =11-8\frac{2}{15} =10\frac{15}{15}-8\frac{2}{15} =2\frac{13}{15}$$

Ответ

а) $$4\frac{3}{8}$$; б) $$6\frac{1}{4}$$; в) $$2\frac{1}{40}$$; г) $$5\frac{1}{4}$$; д) $$7\frac{19}{24}$$; е) $$2\frac{13}{15}$$.