Question

Answer 1

\(a,\dfrac{1}{5};\dfrac{4}{9}\left(MSC=45\right)\)

\(\dfrac{1}{5}=\dfrac{1\times9}{5\times9}=\dfrac{9}{45}\)

\(\dfrac{4}{9}=\dfrac{4\times5}{9\times5}=\dfrac{20}{45}\)

Mà \(\dfrac{9}{45}< \dfrac{20}{45}\Rightarrow\dfrac{1}{5}< \dfrac{4}{9}\)

\(b,\dfrac{2020}{2019};\dfrac{-2020}{-2021}\)

\(\dfrac{-2020}{-2021}=\dfrac{2020}{2021}\)

Mà \(\dfrac{2020}{2019}>\dfrac{2020}{2021}\Rightarrow\dfrac{2021}{2019}>\dfrac{-2020}{-2021}\)

 

Answer 2

a: 1/5=9/45

4/9=20/45

=>1/5<4/9

b: 2020/2019>1>-2020/-2021

Answer 3

\(a,MSC:45\\ \dfrac{1}{5}=\dfrac{1\times9}{5\times9}=\dfrac{9}{45}\\ \dfrac{4}{9}=\dfrac{4\times5}{9\times5}=\dfrac{20}{45}\\ \Rightarrow\dfrac{9}{45}< \dfrac{20}{45}\Rightarrow\dfrac{1}{5}< \dfrac{4}{9}\)

\(b,\dfrac{-2020}{-2021}=\dfrac{2020}{2021}\\ \Rightarrow\dfrac{2020}{2019}>\dfrac{2020}{2021}\Rightarrow\dfrac{2020}{2019}>\dfrac{-2020}{-2021}\)