Question

  Giúp e với

Answer 1

`21/4 : 7 = 21/4 . 1/7 = 21/(4.7) = 21/28=3/4`

`6 . 1/12 : 5/2 = 6 . 1/12 . 2/5 = (6.2)/(12.5) = 12/60 = 1/5`

Answer 2

\(\dfrac{21}{4}:7=\dfrac{21}{4}\times\dfrac{1}{7}=\dfrac{21\times1}{4\times7}=\dfrac{21}{28}=\dfrac{3}{4}\)
\(6\times\dfrac{1}{12}:\dfrac{5}{2}=6\times\dfrac{1}{12}\times\dfrac{2}{5}=\dfrac{6\times1\times2}{12\times5}=\dfrac{12}{60}=\dfrac{1}{5}\)