Ôn tập toán 6

TY

Thực hiện phép tính

a) \(-1\dfrac{2}{3}+\dfrac{3}{4}-\dfrac{1}{2}+2\dfrac{1}{6}\)

b) \(\dfrac{11}{50}\left(-17\dfrac{1}{2}\right)-\dfrac{11}{50}.82\dfrac{1}{2}\)

ND
27 tháng 5 2017 lúc 15:40

a, \(-1\dfrac{2}{3}+\dfrac{3}{4}-\dfrac{1}{2}+2\dfrac{1}{6}\\ =-\dfrac{5}{3}+\dfrac{3}{4}-\dfrac{1}{2}+\dfrac{13}{6}\\ =\dfrac{-5.4+3.3-1.6+13.2}{12}=\dfrac{9}{12}=\dfrac{3}{4}\)

b, \(\dfrac{11}{50}\left(-17\dfrac{1}{2}\right)-\dfrac{11}{50}.82\dfrac{1}{2}\\ =\dfrac{11}{50}.\left(-17\dfrac{1}{2}-82\dfrac{1}{2}\right)=\dfrac{11}{50}.\left(-100\right)=-22\)

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HD
28 tháng 5 2017 lúc 9:26

a) \(-1\dfrac{2}{3}\) + \(\dfrac{3}{4}\) \(-\) \(\dfrac{1}{2}\) + \(2\dfrac{1}{6}\)

=\(-\dfrac{5}{3}\) + \(\dfrac{3}{4}\) \(-\) \(\dfrac{1}{2}\) + \(\dfrac{13}{6}\)\()\)

=\(-\) \(\dfrac{20}{12}\) + \(\dfrac{9}{12}\) \(-\) \(\dfrac{6}{12}\) + \(\dfrac{26}{12}\)

= \((\)\(\dfrac{-20}{12}\) + \(\dfrac{26}{12}\) \()\) + \((\) \(\dfrac{9}{12}\) \(-\) \(\dfrac{6}{12}\) \()\)

= \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\)

= \(\dfrac{3}{4}\)

b)\(\dfrac{11}{50}\) \((\) \(-17\dfrac{1}{2}\) \()\) \(-\) \(\dfrac{11}{50}\) .\(82\dfrac{1}{2}\)

= \(\dfrac{11}{50}\) . \(-\dfrac{35}{2}\) \(-\) \(\dfrac{11}{50}\) . \(\dfrac{165}{2}\)

= \(\dfrac{11}{50}\). \((\) \(-\dfrac{35}{2}\) \(-\) \(\dfrac{165}{2}\) \()\)

=\(\dfrac{11}{50}\). \(-\)\(100\)

= \(-22\)

Chúc bạn học thật tốt nha ! vuihihiok

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NQ
28 tháng 5 2017 lúc 19:53

a) \(-1\dfrac{2}{3}+\dfrac{3}{4}-\dfrac{1}{2}+2\dfrac{1}{6}\)

\(=\dfrac{-5}{3}+\dfrac{3}{4}-\dfrac{1}{2}+\dfrac{13}{6}\)

\(=\dfrac{-20}{12}+\dfrac{9}{12}-\dfrac{6}{12}+\dfrac{26}{12}\)

\(=\dfrac{-20+9-6+26}{12}\)

\(=\dfrac{3}{4}\)

b) \(\dfrac{11}{50}\left(-17\dfrac{1}{2}\right)-\dfrac{11}{50}\cdot82\dfrac{1}{2}\)

\(=\dfrac{11}{50}\cdot\dfrac{-35}{2}-\dfrac{11}{50}\cdot\dfrac{165}{2}\)

\(=\dfrac{11}{50}\left(\dfrac{-35}{2}-\dfrac{165}{2}\right)\)

\(=\dfrac{11}{50}\cdot\left(-100\right)\)

\(=-22\)

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