3/4 va 4/5

Quy dong len mau 20

15/20 va 16/20

15<16

Suy ra 15/20<16/20

3/4<4/5

b)5/8 va 4/9

Quy ddong len 72

40/72 va 32/72

40>32

40/72>32/72

Suy ra :5/8>4/9

b: 23/48<24/48=1/2

1/2=46/92<47/92

=>23/48<47/92

a) \(\dfrac{252525}{666666}=\dfrac{25.10101}{66.10101}=\dfrac{25}{66}\)

⇒\(\dfrac{25}{66}=\dfrac{252525}{666666}\)

b: \(\dfrac{23}{24}=1-\dfrac{1}{24}\)

\(\dfrac{24}{25}=1-\dfrac{1}{25}\)

mà \(-\dfrac{1}{24}>-\dfrac{1}{25}\)

nên \(\dfrac{23}{24}>\dfrac{24}{25}\)

a: \(\dfrac{25}{66}=\dfrac{252525}{666666}\)

b: \(\dfrac{23}{24}=1-\dfrac{1}{24}\)

\(\dfrac{24}{25}=1-\dfrac{1}{25}\)

mà \(-\dfrac{1}{24}< -\dfrac{1}{25}\)

nên \(\dfrac{23}{24}< \dfrac{24}{25}\)

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

\(\dfrac{9}{10}< \dfrac{10}{11}\)

\(\dfrac{125}{251}< \dfrac{127}{253}\)

a 99/110 < 100/110

b 125/251 < 127/253

a 99/110 < 100/110

b 125/251 < 127/253