Question

1. Thực hiện các phép tính:

a. \(\frac{7}{21}\) + \(\frac{9}{-36}\)                                                b. ( 1- \(\frac{1}{5}\) ) ( \(\frac{-3}{10}\) + \(\frac{1}{5}\) )

Answer 1

\(\frac{7}{21}+\frac{9}{-36}=\frac{1}{3}+\frac{-1}{3}=0\)

Answer 2

b. (1-1/5) (-3/10+1/5)

= 4/5.-1/10

=-4/50

Answer 3

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Answer 4

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Answer 5

hi

Answer 6

a) \(\frac{7}{21}+\frac{9}{-36}\)

\(=\frac{1}{3}+\left(-\frac{1}{4}\right)\)

\(=\frac{4}{12}+\left(-\frac{3}{12}\right)\)

\(=\frac{1}{12}\)

b) \(\left(1-\frac{1}{5}\right)\left(-\frac{3}{10}+\frac{1}{5}\right)\)

\(=\frac{4}{5}\left(-\frac{3}{10}+\frac{2}{10}\right)\)

\(=\frac{4}{5}\cdot\left(-\frac{1}{10}\right)\)

\(=-\frac{2}{25}\)