Ta có: 25/26  =  2525/2626 = 25250/26260

Mà :   25250/26260 < 25251/26261

=> 25/26 < 25251/26261

Ta dùng phương pháp phần bù nhé em :)))

Ta có: \(1-\frac{25}{26}=\frac{1}{26}=\frac{1010}{26260}\)

\(1-\frac{25251}{26261}=\frac{1010}{26261}\)

Do \(\frac{1010}{26260}>\frac{1010}{26261}\) nên \(\frac{25}{26}< \frac{25251}{26261}\)

Ta có 25/26=25x1010/26x1010=25250/26260

Vì 25250/26260<1 nên 25250/26260<25250+1/26260+1 hay 25250/26260<25251/26261

Vậy 25/26<25251/26261

a) 

Ta có:

\(c=25\times26261=25\times\left(26260+1\right)=25\times10\times26\times101+25\)

\(d=26\times25251=26\times\left(25250+1\right)=26\times10\times25\times101+26\) 

Vì \(25\times10\times26\times101\) = \(26\times10\times25\times101\) mà \(25< 26\) 

=> \(c< d\) 

b)

Ta có:

\(b=2022\times2024=2022\times\left(2023+1\right)=2022\times2023+2022\) 

\(a=2023\times2023=2023\times\left(2022+1\right)=2023\times2022+2023\)

Vì \(2022\times2023=2023\times2022\) mà \(2022< 2023\) 

=> \(b< a\)

sorry chỉ làm đuoc 25/26 bé hon 25251/26261 

85 / 84 lớn hơn 23/53

85/84 lớn hơn 35/36

a) 

a = 53. 571 = 53. (531 + 40) = 53. 531 + 53. 40 = 53. 531 + 53. (10.4)

= 53. 531 + (53. 10). 4 = 53. 531 + 530. 4

b = 57. 531 = (53 + 4). 531 = 531. (53 + 4) = 531. 53 + 531. 4 

Vì 530 < 531 nên 530. 4 < 531. 4 do đó 53. 531 + 530. 4 < 531. 53 + 531. 4 hay a < b.

Vậy a < b.

b)

a = 25. 26 261 = 25. (26 260 + 1) = 25. 26 260 + 25. 1 = 25. (10. 2 626) + 25

= (25. 10). 2 626 + 25 

= 25. 10. (26. 101) + 25 = 10. 25. 26. 101 + 25;

b = 26. 25 251 = 26. (25 250 + 1) = 26. 25 250 + 26. 1 = 26. (10. 2 525) + 26

= 26. 10. 2 525 + 26 = 26. 10. 25. 101 + 26 = 10. 25. 26. 101 + 26;

Vì 25 < 26 nên 10. 25. 26. 101 + 25 < 10. 25. 26. 101 + 26 hay a < b.

Vậy a < b.

Ta có :1-\(\dfrac{25}{26}=\dfrac{1}{26}=\dfrac{1010}{2626}\)

\(1-\dfrac{25251}{26261}=\dfrac{1010}{26261}\)

Do \(\dfrac{1010}{26261}< \dfrac{1010}{26260}\)nên \(\dfrac{25}{26}< \dfrac{25251}{26261}\)

ta có :

25/26 = 25x1010/26x1010 = 25250/26260

Vì 25250/26260 < 1 nên 25250/26260 <25250 +1 /26260 +1

hay 25250/26260 < 25251/26261

\(\dfrac{25}{26}\)=\(\dfrac{25\cdot10100}{26\cdot10100}\)=\(\dfrac{25250}{26260}\)

Ta có 1-\(\dfrac{25250}{26260}\)=\(\dfrac{1010}{26260}\);1-\(\dfrac{25251}{26261}\)=\(\dfrac{1010}{26261}\)

Vì 26260<26261 nên \(\dfrac{1010}{26260}\)>\(\dfrac{1010}{26261}\)

Vậy \(\dfrac{25}{26}\)>\(\dfrac{25251}{26261}\)

\(a,\dfrac{53}{57}=\dfrac{53.10}{57.10}=\dfrac{530}{570}=1-\dfrac{40}{570}\\ \dfrac{531}{571}=1-\dfrac{40}{571}\\ Vì:\dfrac{40}{570}>\dfrac{40}{571}\Rightarrow1-\dfrac{40}{570}< 1-\dfrac{40}{571}\\ \Leftrightarrow\dfrac{53}{57}< \dfrac{531}{571}\)

\(b,\dfrac{25}{26}=\dfrac{25.1010}{26.1010}=\dfrac{25250}{26260}=1-\dfrac{1010}{26260}\\ \dfrac{25251}{26261}=1-\dfrac{1010}{26261}\\ Vì:\dfrac{1010}{26260}>\dfrac{1010}{26261}\Rightarrow1-\dfrac{1010}{26260}< \dfrac{1010}{26261}\\ \Leftrightarrow\dfrac{25}{26}< \dfrac{25251}{26261}\)