Question

Không quy đồng , hãy so sánh hai phân số :

a) 12/19 và 23/25               b) 21/27 và 23/25

giúpminhf

Answer 1

\(\dfrac{12}{19}< \dfrac{23}{25}\)

\(\dfrac{21}{27}< \dfrac{23}{25}\)

Answer 2

\(\dfrac{12}{19}< \dfrac{23}{25};\dfrac{21}{27}< \dfrac{23}{25}\)

Answer 3

a) \(\dfrac{12}{19}=\dfrac{19}{19}-\dfrac{7}{19}=1-\dfrac{7}{19}\)

\(\dfrac{23}{25}=\dfrac{25}{25}-\dfrac{2}{25}=1-\dfrac{2}{25}\).

-So sánh: \(\dfrac{7}{19}\) và \(\dfrac{2}{25}\).

\(\dfrac{7}{19}=\dfrac{14}{38};\dfrac{2}{25}=\dfrac{14}{175}\Rightarrow\dfrac{7}{19}>\dfrac{2}{25}\left(\dfrac{14}{38}>\dfrac{14}{175}\right)\)

\(\Rightarrow1-\dfrac{7}{19}< 1-\dfrac{2}{25}\) 

\(\Rightarrow\dfrac{12}{19}< \dfrac{23}{25}\)

-Câu b làm tương tự bạn nhé.

 

Answer 4

b)21/27<21/25<23/25