Задание 252 Вариант 3 Самостоятельная работа ГДЗ Дидактические материалы Чесноков 6 класс (Математика)

а)

$$\left(63\frac{9}{20}:(-4{,}7)+9{,}3\right)\cdot\left(-4\frac{1}{5}\right)$$
$$63\frac{9}{20}=63{,}45,\qquad 63{,}45:(-4{,}7)=-13{,}5$$
$$-13{,}5+9{,}3=-4{,}2$$
$$-4{,}2\cdot\left(-4\frac{1}{5}\right)=-4{,}2\cdot(-4{,}2)=17{,}64$$

б)

$$\left(0{,}7-\frac{11}{30}\right)\cdot\left(-1\frac{2}{7}\right)+5\left(0{,}25-\frac{11}{24}\right):\left(2\frac{11}{12}\right)$$
$$0{,}7-\frac{11}{30}=\frac{7}{10}-\frac{11}{30}=\frac{21}{30}-\frac{11}{30}=\frac{10}{30}=\frac{1}{3}$$
$$0{,}25-\frac{11}{24}=\frac{1}{4}-\frac{11}{24}=\frac{6}{24}-\frac{11}{24}=-\frac{5}{24}$$
$$\frac{1}{3}\cdot\left(-1\frac{2}{7}\right)=\frac{1}{3}\cdot\left(-\frac{9}{7}\right)=-\frac{3}{7}$$
$$-\frac{5}{24}:2\frac{11}{12}=-\frac{5}{24}:\frac{35}{12}=-\frac{5}{24}\cdot\frac{12}{35}=-\frac{1}{14}$$
$$5\cdot\left(-\frac{1}{14}\right)=-\frac{5}{14}$$
$$-\frac{3}{7}-\frac{5}{14}=-\frac{6}{14}-\frac{5}{14}=-\frac{11}{14}=-0{,}5$$

Ответ: а) $$17{,}64$$; б) $$-0{,}5$$.