Trước khi so sánh, ta phải rút gọn phân số \(\frac{1212}{1515}\)và \(\frac{12}{15}\)

Rút gọn P/S, ta có: \(\frac{1212:101}{1515:101}\)=\(\frac{12:3}{15:3}\)=\(\frac{3}{5}\)(1)

                                   \(\frac{12:3}{15:3}=\frac{3}{5}\)(2)

Từ (1) và (2) => \(\frac{12}{15}=\frac{1212}{1515}\)

Ta có: \(\frac{12}{15}=\frac{12\div3}{15\div3}=\frac{4}{5}\)

\(\frac{1212}{1515}=\frac{1212\div303}{1515\div303}=\frac{4}{5}\)

Mà \(\frac{4}{5}=\frac{4}{5}\)

\(\Rightarrow\frac{12}{15}=\frac{1212}{1515}\)

Ta có :

 1212/1515=12.102/15.101=12/15

 Vì 12/15=12/15 =>12/15=1212/1515

vậy ...........

    k mk nha

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

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

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

\(\frac{12}{15}\) giữ nguyên

\(\frac{1212}{1515}=\frac{12.101}{15.101}=\frac{12}{15}\)

\(\Rightarrow\frac{12}{15}=\frac{1212}{1515}\)

TA CÓ:

\(\frac{1212}{1515}=\frac{12.101}{15.101}=\frac{12}{15}\)

DỄ THẤY 2 BIIỂU THỨC BẰNG NHAU

\(\Rightarrow\frac{12}{15}=\frac{1212}{1515}\)

5/7>6/21

18/24>15/25

12/13=1212/1313

\(\dfrac{5}{7}\)>\(\dfrac{6}{21}\)

\(\dfrac{18}{24}\)>\(\dfrac{15}{25}\)

\(\dfrac{12}{13}\)=\(\dfrac{1212}{1313}\)

Ta có: \(\frac{1212}{1313}=\frac{12x101}{13x101}=\frac{12}{13}\)

Vậy \(\frac{12}{13}=\frac{1212}{1313}\)

Ta có: 1212/1313 = 12.101/13.101= 12/13

Vì 12/13 = 12/13 nên 12/13 = 1212/1313

Vây...

hai PS đó = nhau .

k cho mình nha

mình nhanh nhất

dễ mà :

1, 4/6=2/3

18/27=2/3

nen 4/6=18/27

2,12/20=3/5

22/55=2/5

vi 3/5 > 2/5

nen 12/20>22/55

3, 5/6=1-1/6

1111/1212=1-101/1212

vi 1/6>101/1212 nen 5/6<1111/1212

đã vào thì kb ik :3 ID ini world:171115964 UWU trung thu sắp đến,ko bt nắng hay mưa,cậu có ai chưa?chưa thì....... ko lấy đc tớ đâu, vì mún ớ cơ

Ta có: \(A=\frac{432143214321}{999999999999}=\frac{4321\times100010001}{9999\times100010001}=\frac{4321}{9999}< \frac{1}{2}\)

\(B=\frac{1212+1212+1212+1212}{1919+1919+1919+1919}=\frac{1212\times4}{1919\times4}=\frac{1212}{1919}=\frac{12\times101}{19\times101}=\frac{12}{19}>\frac{1}{2}\)

Do:\(A< \frac{1}{2}< B\Rightarrow A< B\)

Ta có: \(\frac{1212}{1515}=\frac{12}{15}\)

             =>\(\frac{12}{15}=\frac{1212}{1515}\)

Minh Hà Nguyễn bn chép sai đệ rùi