Вопрос:

Найдите значение выражения: 1) \(2\frac{1}{3}\cdot9-1\frac{1}{3}\cdot\frac{3}{4}-2\frac{2}{7}\cdot3\frac{5}{24}\); 2) \(1\frac{7}{48}\cdot2\frac{2}{5}-(9\frac{1}{6}:\frac{4}{15}+2\frac{5}{9})\cdot\frac{2}{5}\); 3) \((2\frac{1}{4}+4\frac{5}{6}):3\frac{2}{5}-\frac{3}{4}:\frac{3}{5}\); 4) \((8,04:\frac{1}{30}-16,03:\frac{7}{20})\cdot\frac{1}{5}+0,072\cdot\frac{1}{3}\); 5) \((-28,6:57,2+2,68:(-1,34))\cdot(-3,2)\); 6) \((-1,7+3,64):(-1,4):(-0,001):(-0,4)\); 7) \((\frac{9}{14}-(-\frac{5}{21})):(-2\frac{9}{14})\); 8) \((\frac{7}{16}-\frac{31}{40}):(-\frac{17}{24}+\frac{27}{40})\); 9) \(-2\frac{3}{4}-(-8\frac{2}{9}-(-4,5):\frac{9}{14})\cdot2\frac{1}{4}\).

Ответ:

  1. Переведём смешанные числа в неправильные дроби:

    \(\frac{7}{3}\cdot9-\frac{4}{3}\cdot\frac{3}{4}-\frac{16}{7}\cdot\frac{77}{24}=21-1-\frac{22}{3}=\frac{38}{3}\).

  2. \(1\frac{7}{48}\cdot2\frac{2}{5}=\frac{55}{48}\cdot\frac{12}{5}=\frac{11}{4}\).

    \(9\frac{1}{6}:\frac{4}{15}+2\frac{5}{9}=\frac{55}{6}\cdot\frac{15}{4}+\frac{23}{9}=\frac{2659}{72}\).

    \(\frac{11}{4}-\frac{2659}{72}\cdot\frac{2}{5}=\frac{11}{4}-\frac{2659}{180}=-\frac{541}{45}\).

  3. \((2\frac{1}{4}+4\frac{5}{6}):3\frac{2}{5}-\frac{3}{4}:\frac{3}{5}=\frac{85}{12}\cdot\frac{5}{17}-\frac{3}{4}\cdot\frac{5}{3}=\frac{25}{12}-\frac{5}{4}=\frac{5}{6}\).

  4. \((8,04:\frac{1}{30}-16,03:\frac{7}{20})\cdot\frac{1}{5}+0,072\cdot\frac{1}{3}=(241,2-45,8)\cdot0,2+0,024=39,104\).

  5. \((-28,6:57,2+2,68:(-1,34))\cdot(-3,2)=(-0,5-2)\cdot(-3,2)=8\).

  6. \((-1,7+3,64):(-1,4):(-0,001):(-0,4)=1,94:(-1,4):(-0,001):(-0,4)=-\frac{24250}{7}\).

  7. \((\frac{9}{14}-(-\frac{5}{21})):(-2\frac{9}{14})=(\frac{27}{42}+\frac{10}{42}):(-\frac{37}{14})=\frac{37}{42}\cdot(-\frac{14}{37})=-\frac{1}{3}\).

  8. \((\frac{7}{16}-\frac{31}{40}):(-\frac{17}{24}+\frac{27}{40})=(-\frac{27}{80}):(-\frac{1}{30})=\frac{81}{8}\).

  9. \(-2\frac{3}{4}-(-8\frac{2}{9}-(-4,5):\frac{9}{14})\cdot2\frac{1}{4}=-\frac{11}{4}-(-\frac{74}{9}+7)\cdot\frac{9}{4}=-\frac{11}{4}-(-\frac{11}{4})=0\).

Ответ: 1) \(\frac{38}{3}\); 2) \(-\frac{541}{45}\); 3) \(\frac{5}{6}\); 4) \(39,104\); 5) \(8\); 6) \(-\frac{24250}{7}\); 7) \(-\frac{1}{3}\); 8) \(\frac{81}{8}\); 9) \(0\).