18 x \(\left(\frac{1919}{2121}+\frac{888}{999}\right)\)

= 18 x \(\frac{113}{63}\)

= \(\frac{226}{7}\)

Đây có phải tính nhanh không bạn?

\(18\cdot\left(\frac{1919}{2121}+\frac{888}{999}\right)\)

Rút gọn:

\(\frac{1919}{2121}=\frac{1919:101}{2121:101}=\frac{19}{21}\)

\(\frac{888}{999}=\frac{888:111}{999:111}=\frac{8}{9}\)

Ta có:

\(18\cdot\left(\frac{19}{21}+\frac{8}{9}\right)\)

=\(18\cdot\left(\frac{57}{63}+\frac{56}{63}\right)\)

\(=18\cdot\frac{113}{63}\)

\(\frac{18.113}{63}=\frac{9\cdot2\cdot113}{9\cdot7}=\frac{2\cdot113}{7}=\frac{226}{7}\)

Kết quả là \(\frac{226}{7}\)

Đúng thì tk nha!!!

A,(2016*2017-1)/2015*2017+2016

   =2015*2017+2016/2015*2017+2016

   =1

B,18*(1919/2121+888/999)

  =18*(19/21+8/9)

  =18*(19/21)+18*(8/9)=114/7+16=16+2/7+16=32/2/7

c,gọi s=1/2+1/4+...+1/32

2s=1+1/2+...+1/16

2s-s=(1+1/2+...+1/16)-(1/2+1/4+...+1/32)

s=1-1/32=31/32

Can' t  Solve 

ko sao

\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}=\frac{9999}{13635}=\frac{11}{15}\)

1919/2121 = 19/21

191191/212212=191/212

a ) \(\frac{1919}{2121}=\frac{19.101}{21.101}=\frac{19}{21}\)

b) \(\frac{191191}{212212}=\frac{191.1001}{212.1001}=\frac{191}{212}\)

\(a=\frac{1919}{2121}=\frac{1919:1919}{2121:2121}=1,b=\frac{191191}{212212}=\frac{191191:191191}{212212:212212}=1\)

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

\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)

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

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

+) Tử số :

Số các số hạng là : ( 19 - 14 ) : 1 + 1 = 6 ( số )

Tổng là : ( 19 + 14 ) x 6 : 2 = 99

+) Mẫu số :

Số các số hạng là : ( 25 - 20 ) : 1 + 1 = 6 ( số )

Tổng là : ( 25 + 20 ) x 6 : 2 = 135

\(\Leftrightarrow\frac{99}{135}=\frac{11}{15}\)

=82/135

\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)

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

\(=\frac{\left(19+14\right)\left(19-14+1\right):2}{\left(25+20\right)\left(25-20+1\right):2}\)

=\(\frac{33.6:2}{45.6:2}=\frac{33}{45}=\frac{11}{15}\)

\(\frac{1414+1515+1616+1717+1818+1919}{2020+2121+2222+2323+2424+2525}\)

= \(\frac{\left(1414+1919\right)+\left(1515+1818\right)+\left(1616+1717\right)}{\left(2020+2525\right)+\left(2121+2424\right)+\left(2222+2323\right)}\)

= \(\frac{3333+3333+3333}{4545+4545+4545}=\frac{3333}{4545}=\frac{11}{15}\)

t i c k nhé!! 45435436457

11/15

11/15