Упр.762 ГДЗ Ткачёва 6 класс (Математика)

1) ((9 1/2 — 11) : (-0,003))/((4,05 — 3 13/20) · 20);
2) (-1/5 : 0,49 · (-1 1/6))/(3/4 · 1,8 : (-1 1/5) : 0,07);
3) ((2/25 — 1,008) : 4/7)/((3 1/4 — 6 5/9) · 2 2/17).

1) Преобразуем выражение:

$$ \frac{(9\frac{1}{2}-11):(-0{,}003)}{(4{,}05-3\frac{13}{20})\cdot 20} $$

$$ 9\frac{1}{2}-11=-1\frac{1}{2}=-1{,}5 $$

$$ -1{,}5:(-0{,}003)=500 $$

$$ 4{,}05-3\frac{13}{20}=4{,}05-3{,}65=0{,}4 $$

$$ 0{,}4\cdot 20=8 $$

$$ 500:8=62{,}5 $$

2) Вычислим:

$$ \frac{(-\frac{1}{5}:0{,}49)\cdot(-1\frac{1}{6})}{\frac{3}{4}\cdot 1{,}8:(-1\frac{1}{5}):0{,}07} $$

$$ -\frac{1}{5}:0{,}49=-\frac{1}{5}:\frac{49}{100}=-\frac{20}{49} $$

$$ -\frac{20}{49}\cdot\left(-1\frac{1}{6}\right)=-\frac{20}{49}\cdot\left(-\frac{7}{6}\right)=\frac{10}{21} $$

$$ \frac{3}{4}\cdot 1{,}8=\frac{3}{4}\cdot\frac{9}{5}=\frac{27}{20} $$

$$ \frac{27}{20}:(-1\frac{1}{5})=\frac{27}{20}:\left(-\frac{6}{5}\right)=-\frac{9}{8} $$

$$ -\frac{9}{8}:0{,}07=-\frac{9}{8}:\frac{7}{100}=-\frac{225}{14} $$

$$ \frac{10}{21}:\left(-\frac{225}{14}\right)=-\frac{4}{135} $$

3) Найдём значение выражения:

$$ \frac{( \frac{2}{25}-1{,}008):\frac{4}{7}}{(3\frac{1}{4}-6\frac{5}{9})\cdot 2\frac{2}{17}} $$

$$ \frac{2}{25}-1{,}008=0{,}08-1{,}008=-0{,}928 $$

$$ -0{,}928:\frac{4}{7}=-0{,}928\cdot\frac{7}{4}=-1{,}624 $$

$$ 3\frac{1}{4}-6\frac{5}{9}=3\frac{9}{36}-6\frac{20}{36}=-3\frac{11}{36} $$

$$ -3\frac{11}{36}\cdot 2\frac{2}{17}=-\frac{119}{36}\cdot\frac{36}{17}=-7 $$

$$ -1{,}624:(-7)=0{,}232 $$

Ответ

1) $$62{,}5$$; 2) $$-\frac{4}{135}$$; 3) $$0{,}232$$.