Упр.68 Часть 1 ГДЗ Дорофеев Петерсон 6 класс (Математика)

1) (4 1/6•3) :(7•5/21)-1 3/4•4;
2) (3 4/9-1 11/12)•3 9/11+6:12/25-2 1/3;

1) $$\left(4\frac{1}{6}\cdot 3\right):\left(7\cdot \frac{5}{21}\right)-1\frac{3}{4}\cdot 4$$

$$4\frac{1}{6}\cdot 3=\frac{25}{6}\cdot 3=\frac{25}{2}$$
$$7\cdot \frac{5}{21}=\frac{5}{3}$$
$$\frac{25}{2}:\frac{5}{3}=\frac{25}{2}\cdot \frac{3}{5}=\frac{15}{2}=7\frac{1}{2}$$
$$1\frac{3}{4}\cdot 4=\frac{7}{4}\cdot 4=7$$
$$7\frac{1}{2}-7=\frac{1}{2}=0{,}5$$

2) $$\left(3\frac{4}{9}-1\frac{11}{12}\right)\cdot 3\frac{9}{11}+6:\frac{12}{25}-2\frac{1}{3}$$

$$3\frac{4}{9}-1\frac{11}{12}=3\frac{16}{36}-1\frac{33}{36}=2\frac{16}{36}-1\frac{33}{36}=1\frac{19}{36}$$
$$1\frac{19}{36}\cdot 3\frac{9}{11}=\frac{55}{36}\cdot \frac{42}{11}=\frac{5\cdot 7}{6\cdot 1}=\frac{35}{6}=5\frac{5}{6}$$
$$6:\frac{12}{25}=6\cdot \frac{25}{12}=\frac{25}{2}=12\frac{1}{2}$$
$$5\frac{5}{6}+12\frac{1}{2}-2\frac{1}{3}=5\frac{5}{6}+12\frac{3}{6}-2\frac{2}{6}=17\frac{8}{6}-2\frac{2}{6}=15\frac{6}{6}=16$$

Ответ

1) $$0{,}5$$; 2) $$16$$.