Упр.12.5 ГДЗ Рабочая тетрадь Зубарева 6 класс Мнемозина (Математика)
- Выполните вычисления в цепочке.
а)
$$\frac{3}{14}+\frac{9}{14}=\frac{12}{14}=\frac{6}{7}$$
$$\frac{6}{7}-\frac{5}{7}=\frac{1}{7}$$
$$\frac{1}{7}+\frac{5}{21}=\frac{3}{21}+\frac{5}{21}=\frac{8}{21}$$
$$\frac{8}{21}-\frac{15}{21}=-\frac{7}{21}=-\frac{1}{3}$$
$$-\frac{1}{3}+\frac{2}{3}=\frac{1}{3}$$
$$\frac{3}{14}+\frac{9}{14}=\frac{6}{7},\quad \frac{6}{7}-\frac{5}{7}=\frac{1}{7},\quad \frac{1}{7}+\frac{5}{21}=\frac{8}{21},\quad \frac{8}{21}-\frac{15}{21}=-\frac{1}{3},\quad -\frac{1}{3}+\frac{2}{3}=\frac{1}{3}$$
б)
$$\frac{7}{15}+\frac{13}{15}=\frac{20}{15}=\frac{4}{3}$$
$$\frac{4}{3}-\frac{2}{3}=\frac{2}{3}$$
$$\frac{2}{3}+\frac{7}{9}=\frac{6}{9}+\frac{7}{9}=\frac{13}{9}$$
$$\frac{13}{9}-\frac{16}{9}=-\frac{3}{9}=-\frac{1}{3}$$
$$-\frac{1}{3}+\frac{4}{3}=1$$
$$\frac{7}{15}+\frac{13}{15}=\frac{4}{3},\quad \frac{4}{3}-\frac{2}{3}=\frac{2}{3},\quad \frac{2}{3}+\frac{7}{9}=\frac{13}{9},\quad \frac{13}{9}-\frac{16}{9}=-\frac{1}{3},\quad -\frac{1}{3}+\frac{4}{3}=1$$
