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27 tháng 6 2018

\(\frac{-1}{4}\cdot13\frac{9}{11}-0,25\cdot6\frac{2}{11}\)

\(=-0,25\cdot13\frac{9}{11}-0,25\cdot6\frac{2}{11}\)

\(=-0,25\cdot\left(13\frac{9}{11}+6\frac{2}{11}\right)\)

\(=-0,25\cdot\left[\left(13+6\right)+\left(\frac{9}{11}+\frac{2}{11}\right)\right]\)

\(=-0,25\cdot\left[19+1\right]\)

\(=-0,25\cdot20\)

\(=-5\)

25 tháng 4 2018

bạn ơi phải là nhân vói 13 và 9 phần 11 chứ

27 tháng 4 2018

Mk viết nhầm

11 tháng 4 2018

\(A=\frac{7}{10.11}+\frac{7}{11.12}+\frac{7}{12.13}+...+\frac{7}{69.70}\)

   \(=7.\frac{1}{10.11}+7.\frac{1}{11.12}+7.\frac{1}{12.13}+...+7.\frac{1}{69.70}\)

  \(=7.\left(\frac{1}{10.11}+\frac{1}{11.12}+\frac{1}{12.13}+...+\frac{1}{69.70}\right)\) 

   \(=7.\left(\frac{1}{10}-\frac{1}{11}+\frac{1}{11}-\frac{1}{12}+\frac{1}{12}-\frac{1}{13}+...+\frac{1}{69}-\frac{1}{70}\right)\)

   \(=7.\left(\frac{1}{10}-\frac{1}{70}\right)=7.\frac{3}{35}=\frac{3}{5}\)

11 tháng 4 2018

\(A=7.\left(\frac{1}{10}-\frac{1}{70}\right)\)

\(=\frac{6}{70}\)

\(=\frac{3}{35}\)

14 tháng 5 2019

\(9\frac{2}{9}+\frac{2}{3}+7\frac{7}{9}\)

\(=9+\frac{2}{9}+\frac{2}{3}+7+\frac{7}{9}\)

\(=\left(9+7\right)+\left(\frac{2}{9}+\frac{7}{9}\right)+\frac{2}{3}\)

\(=16+1+\frac{2}{3}\)

\(=17+\frac{2}{3}\)

\(=\frac{51}{3}+\frac{2}{3}\)

\(=\frac{53}{3}\)

14 tháng 5 2019

\(\frac{5}{9}.\frac{10}{11}+\frac{5}{9}.\frac{14}{11}-\frac{5}{9}.\frac{15}{11}\)

\(=\frac{5}{9}\left(\frac{10}{11}+\frac{14}{11}-\frac{15}{11}\right)\)

\(=\frac{5}{9}.\frac{9}{11}\)

\(=\frac{5}{11}\)

3 tháng 10 2015

\(=\frac{5}{9}:\left(-\frac{3}{22}\right)+\frac{5}{9}:\left(-\frac{3}{5}\right)\)

\(=\frac{5}{9}.\left[\left(-\frac{22}{3}\right)+\left(-\frac{5}{3}\right)\right]\)

\(=\frac{5}{9}.\left(-9\right)=-5\)

20 tháng 7 2017

     \(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}\)

\(=\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{2}{6}-\frac{2}{8}+\frac{2}{10}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(=\frac{2.\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7.\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}-\frac{2.\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}{7.\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\)

\(=\frac{2}{7}-\frac{2}{7}\)

\(=0\)

1 tháng 4 2019

\(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}=\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(=\frac{2\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{2}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}\)

\(=\frac{2}{7}-\frac{1}{\frac{7}{2}}\)

\(=\frac{2}{7}-\frac{2}{7}=0\)

Study well ! >_<

12 tháng 5 2017

\(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+\frac{1}{13}-\frac{1}{18}\)\(\frac{1}{18}\)

\(\frac{1}{3}-\frac{1}{18}\)

\(\frac{5}{18}\)

12 tháng 5 2017

kết quả là 439/2808

14 tháng 2 2020

Có:

\(A=2010\cdot\left(\frac{\frac{1}{6}+0.25-\frac{1}{8}}{1+1\frac{1}{2}-\frac{3}{4}}+\frac{0.4-\frac{2}{9}+\frac{2}{11}}{3-\frac{15}{9}+1\frac{4}{11}}\right)\)

\(=2010\cdot\left(\frac{\frac{1}{6}+\frac{1}{4}-\frac{1}{8}}{\frac{3}{3}+\frac{3}{2}-\frac{3}{4}}+\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{15}{5}-\frac{15}{9}+\frac{15}{11}}\right)\)

\(=2010\cdot\left[\frac{\frac{1}{2}\cdot\left(\frac{1}{3}+\frac{1}{2}-\frac{1}{4}\right)}{3\cdot\left(\frac{1}{3}+\frac{1}{2}-\frac{1}{4}\right)}+\frac{2\cdot\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{15\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}\right]\)

\(=2010\cdot\left(\frac{\frac{1}{2}}{3}+\frac{2}{15}\right)\)

\(=2010\cdot\left(\frac{\frac{5}{2}}{15}+\frac{2}{15}\right)\\ =2010\cdot\left(\frac{\frac{5}{2}+2}{15}\right)\)

\(=2010\cdot\frac{\frac{9}{2}}{15}\\ =\frac{2010\cdot\frac{9}{2}}{15}\\ =\frac{1005\cdot9}{15}\\ =201\cdot3\\ =603\)