Question

tính

a) \(\dfrac{4}{5}\)\(+\)\(\dfrac{2}{7}\)\(-\)\(\dfrac{7}{10}\)

b) \(\dfrac{1}{12}\)\(-\)\(\left(\dfrac{-1}{6}-\dfrac{1}{4}\right)\)

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Answer 1

a,\(\dfrac{4}{5}+\dfrac{2}{7}-\dfrac{7}{10}=\dfrac{38}{35}-\dfrac{7}{10}=\dfrac{27}{70}\)

b,\(\dfrac{1}{12}-\left(\dfrac{-1}{6}-\dfrac{1}{4}\right)=\dfrac{1}{12}+\dfrac{5}{12}=\dfrac{1}{2}\)

Answer 2

a) \(\dfrac{4}{5}+\dfrac{2}{7}-\dfrac{7}{10}\)

\(=\dfrac{4.14}{5.14}+\dfrac{2.10}{7.10}-\dfrac{7.7}{10.7}\)

\(=\dfrac{56+20-49}{70}\)

\(=\dfrac{27}{70}\)

Answer 3

b) \(\dfrac{1}{12}-\left(\dfrac{-1}{6}-\dfrac{1}{4}\right)\)

\(=\dfrac{1}{12}+\dfrac{1}{6}+\dfrac{1}{4}\)

\(=\dfrac{1}{12}+\dfrac{2}{12}+\dfrac{3}{12}\)

\(=\dfrac{6}{12}=\dfrac{1}{2}\)