Ai làm đúng và nhanh nhất mk k cho

cái thứ hai lớn hơn

Ta có : \(\frac{1212+1313+1414+1515+1616}{1717+1818+1919+2020+2121}=\frac{12+13+14+15+16}{17+18+19+20+21}=\frac{28\cdot\frac{5}{2}}{38\cdot\frac{5}{2}}=\frac{14}{19}\)

Dễ thấy \(\frac{111111}{666665}< \frac{1}{2}\) ( do 111111 < 666665/2 ) và \(\frac{14}{19}>\frac{1}{2}\) ( do 14 > 19/2 )

Vậy \(\frac{111111}{666665}< \frac{1212+1313+1414+1515+1616}{1717+1818+1919+2020+2121}\)

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 = \(\dfrac{11}{15}\)

=\(\frac{14x101+15x101+16x101+18x101+19x101}{20x101+21x101+22x101+23x101+24x101+25x101}\)

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

=\(\frac{14+15+16+17+18}{20+21+22+23+24+25}=\frac{99}{135}=\frac{11}{15}\)

\(S=\left(1-\dfrac{1}{2}\right)\left(1-\dfrac{1}{3}\right)\left(1-\dfrac{1}{4}\right).....\left(1-\dfrac{1}{2022}\right)\left(1-\dfrac{1}{2023}\right)\)

\(=\dfrac{1}{2}.\dfrac{2}{3}.\dfrac{3}{4}....\dfrac{2022}{2023}\)

\(=\dfrac{1.2.3....2022}{2.3.4....2023}\)

\(=\dfrac{1}{2023}\)

Để mình giúp bạn nha !!!

A) \(\frac{7}{15}\)

B) 4,391

1414+1515+1616+1717+1818+1919/2020+2121+2222+2323+2424+2525

=14.101+15.101+16.101+17.101+18.101+19.101/20.101+21.101+22.101+23.101+24.101+25.101

=14+15+16+17+18+19/20+21+22+23+24+25

=99/135

=11/15

HELP MEEEEEEEEEEEE!

toán lớp 7 nha

tam giac ABC vuong moi lam cau b dc