Question

thuc hien phep tinh:

a,\(1\dfrac{1}{2}\). \(2\dfrac{1}{3}\)+ \(1\dfrac{1}{3}\). \(\dfrac{1}{2}\)

b,\(\dfrac{1}{9}\).\(\dfrac{2}{145}\)\(-4\dfrac{1}{3}\). \(\dfrac{2}{145}\)+\(\dfrac{2}{145}\)

Answer 1

Giải:

a) \(1\dfrac{1}{2}.2\dfrac{1}{3}+1\dfrac{1}{3}.\dfrac{1}{2}\)

\(=\dfrac{3}{2}.\dfrac{7}{3}+\dfrac{4}{3}.\dfrac{1}{2}\)

\(=\dfrac{21}{6}+\dfrac{4}{6}\)

\(=\dfrac{1}{6}\left(21+4\right)\)

\(=\dfrac{1}{6}.25=\dfrac{25}{6}\)

b) \(\dfrac{1}{9}.\dfrac{2}{145}-4\dfrac{1}{3}.\dfrac{2}{145}+\dfrac{2}{145}\)

\(=\dfrac{1}{9}.\dfrac{2}{145}-\dfrac{13}{3}.\dfrac{2}{145}+\dfrac{2}{145}\)

\(=\dfrac{2}{145}\left(\dfrac{1}{9}-\dfrac{13}{3}+1\right)\)

\(=\dfrac{2}{145}\left(-\dfrac{29}{9}\right)\)

\(=-\dfrac{2}{45}\)

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