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

\(\frac{121212+12121212-1212}{363636+36363636-3636}\)

\(=\frac{12.10101+12.1010101-12.101}{36.10101+36.1010101-36.101}\)

\(=\frac{12\left(10101+1010101-101\right)}{36\left(10101+1010101-101\right)}\)

\(=\frac{12}{12.3}\)

\(=\frac{1}{3}\)

Ta có: \(\frac{121212+12121212-1212}{363636+36363636-3636}\)

           =\(\frac{12\times\left(10101+1010101-101\right)}{36\times\left(10101+1010101-101\right)}\)

           =\(\frac{12}{36}\)

           =\(\frac{1}{3}\)

1919/1212+51515151/36363636

=19/12+51/36

=3

bang 3

1212/1515 = 4/5

363636/545454 = 2/3

~hok tốt~

#Trang#

a)1212/1515=4/5.Cả tử và mẫu chia cho 303

b)363636/545454=2/3.Cả tử và mẫu chia cho 181818

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

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

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

=\(\frac{19}{12}\)+ \(\frac{51}{36}\)

= 3

1919/1212 + 51515151/36363636 = 3.

Ai tk cho mình mình tk lại.

bằng 3 nhé