Question

Bài 3: Thực hiện phép tính:

a) \(\dfrac{-2}{3}\)+(-0,6)-\(\dfrac{7}{10}\);                                    b) \(\dfrac{4}{3}\)+(-1,5)+\(\dfrac{5}{12}\);

c) \(\dfrac{-5}{6}\)-1\(\dfrac{5}{7}\).\(\dfrac{-21}{15}\);                                   d) \((\dfrac{-3}{11}:\dfrac{5}{22})\).\((\dfrac{-15}{3}:\dfrac{26}{3})\).

Answer 1

a)\(\dfrac{-2}{3}+\left(-0,6\right)-\dfrac{7}{10}\)

\(=\dfrac{-2}{3}+\dfrac{-3}{5}-\dfrac{7}{10}\)

\(=\dfrac{-20}{30}+-\dfrac{18}{30}-\dfrac{21}{30}\)

\(=\dfrac{\left(-20\right)+\left(-18\right)-21}{30}\)

\(=-\dfrac{59}{30}\)

b)\(\dfrac{4}{3}+\left(-1,5\right)+\dfrac{5}{12}\)

\(=\dfrac{4}{3}+\dfrac{-3}{2}+\dfrac{5}{12}\)

\(=\dfrac{16}{12}+\dfrac{-18}{12}+\dfrac{5}{12}\)

=\(\dfrac{3}{12}=\dfrac{1}{4}\)

Answer 2

c,\(\dfrac{-5}{6}-1\dfrac{5}{7}.\dfrac{-21}{15}\)

\(=\dfrac{-5}{6}-\dfrac{12}{7}.-\dfrac{21}{15}\)

\(=-\dfrac{5}{6}-\dfrac{-12}{5}\)

\(=\dfrac{47}{30}\)

d,\(\left(-\dfrac{3}{11}\div\dfrac{5}{22}\right).\left(-\dfrac{15}{3}\div\dfrac{26}{3}\right)\)

\(=\left(-\dfrac{3}{11}.\dfrac{22}{5}\right).\left(-\dfrac{15}{3}.\dfrac{3}{26}\right)\)

\(=-\dfrac{6}{5}.\dfrac{-15}{26}\)

\(=\dfrac{9}{13}\)