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15 tháng 8 2016

a)

\(\frac{1}{2}-0,25+0,2\)

\(=\frac{1}{2}-\frac{1}{4}+\frac{1}{5}\)

\(=\frac{10}{20}-\frac{5}{20}+\frac{4}{20}\)

\(=\frac{10-5+4}{20}\)

\(=\frac{1}{20}\)

b)\(\frac{7}{6}-0,875+0,7\)

\(=\frac{7}{6}-\frac{7}{8}+\frac{7}{10}\)

\(=\frac{140}{120}-\frac{105}{120}+\frac{84}{120}\)

\(=\frac{140-105+84}{120}\)

\(=\frac{119}{120}\)

15 tháng 8 2016

tr phân số sao tách tử mẫu riêng ra lm 2 câu lm j v

31 tháng 8 2016

\(B=\frac{0,6-\frac{3}{11}+\frac{3}{13}}{1,4-\frac{7}{11}+\frac{7}{13}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}\) 

\(B=\frac{\frac{3}{5}-\frac{3}{11}+\frac{3}{13}}{\frac{7}{5}-\frac{7}{11}+\frac{7}{13}}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(B=\frac{3\left(\frac{1}{5}-\frac{1}{11}+\frac{1}{13}\right)}{5\left(\frac{1}{5}-\frac{1}{11}+\frac{1}{13}\right)}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{7\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\)

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

\(B=\frac{3}{5}-\frac{2}{7}=\frac{11}{35}\)

18 tháng 6 2018

1)

\(\dfrac{0,375-0,3+\dfrac{3}{11}+\dfrac{3}{12}}{-0,625+0,5-\dfrac{5}{11}-\dfrac{5}{12}}+\dfrac{1,5+1-0,75}{2,5+\dfrac{5}{3}-1,25}\)
\(=\dfrac{\dfrac{3}{8}-\dfrac{3}{10}+\dfrac{3}{11}+\dfrac{3}{12}}{-\dfrac{5}{8}+\dfrac{5}{10}-\dfrac{5}{11}-\dfrac{6}{12}}+\dfrac{\dfrac{3}{2}+\dfrac{3}{3}-\dfrac{3}{4}}{\dfrac{5}{2}+\dfrac{5}{3}-\dfrac{5}{4}}\)
\(=\dfrac{3\left(\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}\right)}{-5\left(\dfrac{1}{8}-\dfrac{1}{10}+\dfrac{1}{11}+\dfrac{1}{12}\right)}+\dfrac{3\left(\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}\right)}{5\left(\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{4}\right)}\)
\(=\dfrac{3}{-5}+\dfrac{3}{5}\)
\(=-\dfrac{3}{5}+\dfrac{3}{5}\)
\(=0\)

21 tháng 11 2018

\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}\cdot\frac{\frac{1}{3}-0,25+0,2}{1\frac{1}{6}-0,875+0,7}\)

\(=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{2.\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}\cdot\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

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

10 tháng 9 2021

ko biết viết chên này

25 tháng 12 2017

\(\dfrac{\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}}{\dfrac{2}{3}-\dfrac{2}{7}-\dfrac{2}{13}}\cdot\dfrac{\dfrac{1}{3}-0,25+0,2}{1\dfrac{1}{6}-0,875+0,7}+\dfrac{6}{7}\)

\(=\dfrac{\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}}{2\cdot\left(\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}\right)}\cdot\dfrac{\dfrac{2}{6}-\dfrac{2}{8}+\dfrac{2}{10}}{\dfrac{7}{6}-\dfrac{7}{8}+\dfrac{7}{10}}+\dfrac{6}{7}\)

\(=\dfrac{1}{2}\cdot\dfrac{2\cdot\left(\dfrac{1}{6}-\dfrac{1}{8}+\dfrac{1}{10}\right)}{7\cdot\left(\dfrac{1}{6}-\dfrac{1}{8}+\dfrac{1}{10}\right)}+\dfrac{6}{7}\)

\(=\dfrac{1}{2}\cdot\dfrac{2}{7}+\dfrac{6}{7}\)

\(=\dfrac{1}{7}+\dfrac{6}{7}=\dfrac{7}{7}=1\)

25 tháng 12 2017

\(\dfrac{\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}}{\dfrac{2}{3}-\dfrac{2}{7}-\dfrac{2}{13}}.\dfrac{\dfrac{1}{3}-0,25+0,2}{1\dfrac{1}{6}+0,875+0,7}+\dfrac{6}{7}.\)

\(=\dfrac{\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}}{2\left(\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}\right)}.\dfrac{\dfrac{2}{6}-\dfrac{2}{8}+\dfrac{2}{10}}{\dfrac{7}{6}-\dfrac{7}{8}+\dfrac{7}{10}}+\dfrac{6}{7}.\)

\(=\dfrac{1}{2}.\dfrac{2\left(\dfrac{1}{6}+\dfrac{1}{8}+\dfrac{1}{10}\right)}{7\left(\dfrac{1}{6}+\dfrac{1}{8}+\dfrac{1}{10}\right)}+\dfrac{6}{7}.\)

\(=\dfrac{1}{2}.\dfrac{2}{7}+\dfrac{6}{7}.\)

\(=\dfrac{1}{7}+\dfrac{6}{7}=\dfrac{7}{7}=1.\)

Vậy.....

1 tháng 9 2015

\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{1}{3}-0,25+0,2}{1\frac{1}{6}-0,875+0,7}+\frac{6}{7}\)

\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{2\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}.\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}+\frac{6}{7}\)

\(\frac{1}{2}.\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{7.\frac{1}{2}.\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}+\frac{6}{7}\)

\(\frac{1}{2}.\frac{1}{\frac{7}{2}}+\frac{6}{7}\)

\(\frac{1}{2}.\frac{2}{7}+\frac{6}{7}\)

\(\frac{1}{7}+\frac{6}{7}\)

= 1

3 tháng 10 2019

\(A=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{1}{3}-0,25+0,2}{\frac{7}{6}-0,875+0,7}+\frac{6}{7}\)

\(=\frac{1}{2}.\frac{2}{7}+\frac{6}{7}=1\)

\(A=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{1}{3}-0,25+0,2}{\frac{7}{6}-0,875+0,7}+\frac{6}{7}\)

\(=\frac{1}{2}-\frac{1}{2}-\frac{1}{2}.\frac{5}{6}-\frac{25}{\frac{100}{-\frac{875}{1000}}}+\frac{6}{7}\)

\(=-\frac{1}{2}.\frac{5}{6}-\frac{25}{\frac{100}{\frac{-87,5}{100}}}+\frac{6}{7}\)

\(=-\frac{1}{2}.\frac{5}{6}-\frac{25}{-87,5}+\frac{6}{7}\)

đến đây tự lm == 

25 tháng 8 2017

\(=\dfrac{\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}}{2\left(\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}\right)}.\dfrac{\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}}{\dfrac{7}{6}-\dfrac{7}{8}+\dfrac{7}{10}}+\dfrac{6}{7}\)

\(=\dfrac{1}{2}.\dfrac{\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}}{\dfrac{7}{2}\left(\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}\right)}+\dfrac{6}{7}\)

\(=\dfrac{1}{2}.\dfrac{2}{7}+\dfrac{6}{7}=\dfrac{1}{7}+\dfrac{6}{7}=1\)

9 tháng 7 2017

\(B=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}\times\frac{\frac{1}{3}-0.25+0.2}{1\frac{1}{6}-0.875+0.7}+\frac{6}{7}\)\(\frac{6}{7}\)

\(B=\frac{1\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}{2\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}\times\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}+\frac{6}{7}\)

\(=\frac{1}{2}\times\frac{1\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}{7\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\times\frac{6}{7}\)

\(=\frac{1}{2}\times\frac{1\left(\frac{2}{6}-\frac{2}{8}+\frac{2}{10}\right)}{7\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\times\frac{6}{7}\)

\(=\frac{1}{2}\times\frac{1\times1}{7\times2}\times\frac{6}{7}=\frac{6}{2\times7\times2\times7}=\frac{3}{98}\)

9 tháng 7 2017

xin lỗi mình làm sai một tí, bây giờ mình làm lại nha