ta có: \(\frac{1717}{2525}=\frac{17}{25}\)

\(\frac{515151}{727272}=\frac{51}{72}=\frac{17}{24}>\frac{17}{25}\)

\(\Rightarrow\frac{1717}{2525}< \frac{515151}{727272}\)

Ta có:

\(\frac{1717}{2525}=\frac{17}{25}\)

\(\frac{515151}{727272}=\frac{51}{72}=\frac{17}{24}\)

Mà: \(\frac{17}{25}< \frac{17}{24}\)

\(\Rightarrow\frac{1717}{2525}< \frac{515151}{727272}\)

tks 2 bạn nha

A)1212/1313<1313/1414.B)1717/2525<515151/727272.23/28,7/9,5/7,11/18

\(\dfrac{121212}{131313}=\dfrac{121212:10101}{131313:10101}=\dfrac{12}{13}=1-\dfrac{1}{13}\)

\(\dfrac{1313}{1414}=\dfrac{1313:101}{1414:101}=\dfrac{13}{14}=1-\dfrac{1}{14}\)

Vì \(\dfrac{1}{13}>\dfrac{1}{14}\) nên \(\dfrac{12}{13}< \dfrac{13}{14}\) hay \(\dfrac{1212}{1313}< \dfrac{1313}{1414}\)

b) \(\dfrac{1717}{2525}=\dfrac{1717:101}{2525:101}=\dfrac{17}{25}=\dfrac{51}{75}\)

\(\dfrac{515151}{727272}=\dfrac{515151:10101}{727272:10101}=\dfrac{51}{72}\)

Vì \(\dfrac{51}{75}< \dfrac{51}{72}\) nên \(\dfrac{17}{25}< \dfrac{51}{72}\) hay \(\dfrac{1717}{2525}< \dfrac{515151}{727272}\)

a) \(\dfrac{1212}{1313}=\dfrac{101x12}{101x13}=\dfrac{12}{13}< \dfrac{12+1}{13+1}=\dfrac{13}{14}\)

\(\dfrac{1313}{1414}=\dfrac{101x13}{101x14}=\dfrac{13}{14}\)

Vậy \(\dfrac{1212}{1313}< \dfrac{1313}{1414}\)

Làm tương tự câu b

a) 1212/1313 = 12/13 = 1 - 1/13

1313/1414 = 13/14 = 1 - 1/14

Do 13 < 14 nên 1/13 > 1/14

⇒ 1 - 1/13 < 1 - 1/14

Vậy 1212/1313 < 1313/1414

b) 1717/2525 = 17/25

515151/727272 = 51/72 = 17/24

Do 25 > 24 nên 17/25 < 17/24

Vậy 1717/2525 < 515151/727272

\(\frac{2525}{1717}=\frac{2525:101}{1717:101}=\frac{25}{17}\)

\(\frac{225}{126}=\frac{225:9}{126:9}=\frac{25}{14}\)

Vì 14 < 17

\(=>\frac{25}{14}>\frac{25}{17}=>\frac{2525}{1717}< \frac{225}{126}\)

Kết quả là

   2525/1717 < 225/126

       Đs...

\(\frac{2525}{1717}\)=\(\frac{2525:101}{1717:101}\)=\(\frac{25}{17}\)

\(\frac{225}{126}\)=\(\frac{225:9}{126:9}\)=\(\frac{25}{14}\)

Có 25=25 mà 17<14 nên \(\frac{25}{17}\)<\(\frac{25}{14}\)hay \(\frac{2525}{1717}\)< \(\frac{225}{126}\)

Vậy \(\frac{2525}{1717}\)< \(\frac{225}{126}\)

CHÚC BẠN HỌC GIỎI NHA

Vì 14/14 = 1; 15/15 = 1 ; ....

⇔ Tổng trên là 6 < 11.

Vì 20/20 = 1 ; 21/21 = 1 ; ...

⇒ Tổng trên là 6 < 15.

\(\frac{1717}{6969}=\frac{17}{69};\frac{2525}{9999}=\frac{25}{99}\)

Ta có : khoảng cách ở tử và mẫu càng bé thì phân số càng lớn

 69 - 17 = 52

 99 - 25 = 74

Vì 52 < 74 

\(\Rightarrow\frac{1717}{6969}>\frac{2525}{9999}\)

A = \(\dfrac{1414+1515+1616+1717+1818+1919}{2020+2121+2022+2323+2424+2525}\)

A = \(\dfrac{101\times\left(14+15+16+17+18+19\right)}{101\times\left(20+21+22+23+24+25\right)}\)

A = \(\dfrac{99}{135}\) 

A = \(\dfrac{11}{15}\)

-2525/2929 > -217/245

-2525/2929 > -217/245

-2525/2929 < -217/245

Đề bài kiểu gì vậy?VIết rõ hơn đi

rối mắt á

1414+1515+1616+1717+1818+1919

2020+2121+2222+2323+2424+2525