Đặt 

\(A=210.\left(\frac{111111}{121212}+\frac{111111}{202020}+\frac{111111}{303030}+\frac{111111}{424242}+\frac{111111}{565656}+\frac{111111}{727272}+\frac{111111}{909090}\right)\)

     \(=210.\left(\frac{11}{12}+\frac{11}{20}+\frac{11}{30}+\frac{11}{42}+\frac{11}{56}+\frac{11}{72}+\frac{11}{90}\right)\)

    \(=210.11\left(\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}+\frac{1}{90}\right)\)

     \(=2310.\left(\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}+\frac{1}{9.10}\right)\)

    \(=2310.\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}\right)\)

     \(=2310.\left(\frac{1}{3}-\frac{1}{10}\right)\)

       \(=2310.\frac{7}{30}\)

        \(=539\)

210.(111111/121212 +111111/202020+11111/303030 + 111111/424242 +111111/565656 +111111/727272 +111111/909090)

= 210 . ( 11/12+11/20+11/42+11/56+11/72+11/90)

= 210.(11.(1/12+1/20+1/42+1/56+1/72+1/90))

=210.(11(1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10))

=210.(11.(1/3-1/10))

=210.(11.7/30)

=210.77/30

=593

 T I C K    GIÙM MIK

C=10101(10/222222+5/222222+8/222222)

C=10101.23/222222

C=232323/222222

I=10101(5/111111+5/222222+4/3.7.11.13.37)

I=10101(5/111111+5/222222+4/111111)

I=10101(10/222222+5/222222+8/222222)

I=10101.23/222222

I=232323/222222

\(I=\frac{7}{22}\)

\(H=\frac{2103}{100}=21,03\)

Nguyễn Triệu Yến Nhi chép sai đề rồi!!!

\(\left(\frac{151515}{60606}+\frac{151515}{121212}+\frac{151515}{202020}+\frac{151515}{303030}+\frac{151515}{424242}\right)\times\frac{28}{15}\)

\(=\left(\frac{5}{2}+\frac{5}{4}+\frac{3}{4}+\frac{1}{2}+\frac{5}{14}\right)\times\frac{28}{15}\)

\(=\frac{75}{14}\times\frac{28}{15}\)

\(=10\)

= ( 1/4 + 5/4 + 3/4 + 1/2 + 5/14) . 28/15
= [ 9/4 +( 7/14 + 5/14)] . 28/15
=        (9/4 + 6/7) . 28/15
= 87/28 . 28/15 = 87/15 = 29/5
 

= 10,ai k mk thì mk k lại

\(H=\left(9\frac{30303}{80808}+7\frac{303030}{484848}\right)+4.03\)

\(H=\left(\frac{75}{8}+\frac{61}{8}\right)+\frac{403}{100}\)

\(H=17+\frac{403}{100}\)

\(H=\frac{2103}{100}\)

\(I=10101.\left(\frac{5}{111111}+\frac{5}{222222}-\frac{4}{3.7.11.13.37}\right)\)

\(I=10101.\left(\frac{5}{111111}+\frac{5}{222222}-\frac{4}{111111}\right)\)

\(I=10101.\left(\frac{5}{111111}-\frac{4}{111111}+\frac{5}{222222}\right)\)

\(I=10101.\left(\frac{1}{111111}+\frac{5}{222222}\right)\)

\(I=10101.\frac{7}{222222}\)

\(I=\frac{7}{22}\)

A=7/22

Ai thấy đúng thì k cho mik nha

A=6/11 bạn ơi

\(A=10101.\left(\frac{5}{111111}+\frac{5}{222222}-\frac{4}{3.7.11.13.37}\right)\)

\(A=10101.\left(\frac{5}{111111}+\frac{5}{222222}-\frac{4}{111111}\right)\)

\(A=10101.\left(\frac{10}{222222}+\frac{5}{222222}-\frac{8}{222222}\right)\)

\(A=10101.\left(\frac{7}{222222}\right)\)

\(A=\frac{70707}{222222}\)

\(A=\frac{7}{22}\)

Vậy A = \(\frac{7}{22}\)

Chúc bạn học tốt!

111111=3.7.11.13.37

222222=2.3.7.11.13.37

THẾ ZÔ LM TIẾP

Làm rõ hơn đi bạn 

\(B=10101\cdot\left(\dfrac{5}{111111}+\dfrac{5}{222222}-\dfrac{4}{111111}\right)\)

\(=10101\cdot\left(\dfrac{2}{222222}+\dfrac{5}{222222}\right)\)

\(=10101\cdot\dfrac{1}{31746}=\dfrac{7}{22}\)