Question

Tính :

a) \(\dfrac{10}{21}.\dfrac{14}{25}\)

b) ( - 1,08 - \(\dfrac{2}{5}\)) : \(\dfrac{4}{7}\)

Answer 1

a) \(\dfrac{10}{21}.\dfrac{14}{25}=\dfrac{2.2}{3.5}=\dfrac{4}{15}\)

b) \(\left(-1,08-\dfrac{2}{5}\right):\dfrac{4}{7}\)

\(=\left(-\dfrac{27}{25}-\dfrac{2}{5}\right):\dfrac{4}{7}\)

\(\dfrac{-37}{25}:\dfrac{4}{7}=\dfrac{-259}{100}\)

Answer 2

\(\dfrac{10}{21}.\dfrac{14}{25}=\dfrac{10.14}{21.25}=\dfrac{2.5.2.7}{3.7.5.5}=\dfrac{2.2}{3.5}=\dfrac{4}{15}\)

\(\left(-1,08-\dfrac{2}{5}\right):\dfrac{4}{7}=-1,48:\dfrac{4}{7}=-2,95\)

Answer 3

Cái này bạn có thể bấm máy tính Casio nhé!