\(\frac{43}{45}>\frac{43}{49}>\frac{27}{49}\)

a) ta có:  \(1-\frac{2012}{2013}=\frac{1}{2013}\)

                 \(1-\frac{2013}{2014}=\frac{1}{2014}\)

mà \(\frac{1}{2013}>\frac{1}{2014}\) nên   \(\frac{2013}{2014}>\frac{2012}{2013}\)

sao giống lớp 4 thế ta

b, \(\dfrac{7}{13}\) và \(\dfrac{17}{23}\) 

\(\dfrac{7}{13}\) <  \(\dfrac{7+10}{13+10}\) = \(\dfrac{17}{23}\)

Vậy \(\dfrac{7}{13}\) < \(\dfrac{17}{23}\) 

\(\dfrac{12}{48}\) =  \(\dfrac{12:12}{48:12}\)  = \(\dfrac{1}{4}\) 

\(\dfrac{13}{47}\) > \(\dfrac{13}{52}\) = \(\dfrac{13:13}{52:13}\) = \(\dfrac{1}{4}\) 

Vậy  \(\dfrac{12}{48}\) < \(\dfrac{13}{47}\) 

>

>

>

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

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

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

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.

hai phân số nào em nhở?

và phân số nào nữa?

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

ko quy dòng á ??????????????

khó nhể

Do \(\frac{23}{28}< \frac{23}{27}< \frac{24}{27}\)

=> 23/28 < 24/27

Ủng hộ mk nha ^_-

\(\frac{23}{28}\)<\(\frac{24}{27}\)nha bn!

23/28,24/27