\(\frac{24}{29}+\frac{7}{38}+\frac{31}{38}+\frac{5}{29}=\left(\frac{24}{29}+\frac{5}{29}\right)+\left(\frac{7}{38}+\frac{31}{38}\right)=\frac{29}{29}+\frac{38}{38}=1+1=2\)

= 2 nha bn

24/29+7/38+31/38+5/29

=(24/29+5/29)+(7/38+31/38)

=29/29+38/38

=1+1

=2

569/232 bạn nhé mình chắc 100%

=2 bạn nhé. nhớ cho mình

chúc bạn học tốt

đáp án là 2 k mình đúng đi

= 2.

Đúng 100% luôn! 

Ai tk cho mình mình tk lại.

2015/2011>1996/1992

* 100 là cái gì vậy .nhân à

79600 nha

=79600

A)  7/38 x 9/11 +7/38 x 4/11 -7/38 x 2/11

=7/38.(9/11+4/11-2/11)

=7/38

B) 5/31 x 21/25 + 5/31 x -7/10 - 5/31 x 9/20

=5/31.(21/25-7/10-9/20)

=5/31.(-31/100)

=-1/20

=\(\dfrac{1}{18}-\dfrac{1}{23}+\dfrac{1}{23}-\dfrac{1}{24}+\dfrac{1}{24}-\dfrac{1}{31}+\dfrac{1}{31}-\dfrac{1}{33}+\dfrac{1}{33}-\dfrac{1}{37}+\dfrac{1}{37}-\dfrac{1}{38}\)

=\(\dfrac{1}{18}-\dfrac{1}{38}=\dfrac{19-9}{38x9}=\dfrac{10}{342}=\dfrac{5}{171}\)

\(\dfrac{5}{18\times23}+\dfrac{1}{23\times24}+\dfrac{7}{24\times31}+\dfrac{2}{31\times33}+\dfrac{4}{33\times37}+\dfrac{1}{37\tímes38}\)

\(\dfrac{23-18}{18\times23}+\dfrac{24-23}{23\times24}+\dfrac{31-24}{24\times31}+\dfrac{33-31}{31\times33}+\dfrac{37-33}{33\times37}+\dfrac{38-37}{37\times38}\)

\(\dfrac{23}{18\times23}-\dfrac{18}{18\times23}+\dfrac{24}{23\times24}-\dfrac{23}{23\times24}+\dfrac{31}{24\times31}-\dfrac{24}{24\times31}+\dfrac{33}{31\times33}-\dfrac{31}{31\times33}+\dfrac{37}{33\times37}-\dfrac{33}{33\times37}+\dfrac{38}{37\times38}-\dfrac{37}{37\times38}\)

\(\dfrac{1}{18}-\dfrac{1}{23}+\dfrac{1}{23}-\dfrac{1}{24}+\dfrac{1}{24}-\dfrac{1}{31}+\dfrac{1}{31}-\dfrac{1}{33}+\dfrac{1}{33}-\dfrac{1}{37}+\dfrac{1}{37}-\dfrac{1}{38}\)

\(\dfrac{1}{18}-\dfrac{38}=\dfrac{5}{171}\)

Sửa lại chỗ cuối đề dòng \(1\) là \(\dfrac{1}{37\times38}\) và ở cuối bài là \(=\dfrac{1}{18}-\dfrac{1}{38}=\dfrac{5}{171}\)
 

1/

$M=\frac{1}{3.8}+\frac{1}{8.13}+\frac{1}{13.18}+....+\frac{1}{33.38}$

$5M=\frac{8-3}{3.8}+\frac{13-8}{8.13}+\frac{18-13}{13.18}+...+\frac{38-33}{33.38}$

$=\frac{1}{3}-\frac{1}{8}+\frac{1}{8}-\frac{1}{13}+\frac{1}{13}-\frac{1}{18}+....+\frac{1}{33}-\frac{1}{38}$
$=\frac{1}{3}-\frac{1}{38}=\frac{35}{114}$

$\Rightarrow M=\frac{35}{114}:5=\frac{7}{114}$

2/

$N=\frac{1}{3.10}+\frac{1}{10.17}+\frac{1}{17.24}+\frac{1}{24.31}+\frac{1}{31.38}$

$7N=\frac{10-3}{3.10}+\frac{17-10}{10.17}+\frac{24-17}{17.24}+\frac{31-24}{24.31}+\frac{38-31}{31.38}$

$=\frac{1}{3}-\frac{1}{10}+\frac{1}{10}-\frac{1}{17}+\frac{1}{17}-\frac{1}{24}+\frac{1}{24}-\frac{1}{31}+\frac{1}{31}-\frac{1}{38}$

$=\frac{1}{3}-\frac{1}{38}=\frac{35}{114}$

$\Rightarrow N=\frac{35}{114}:7=\frac{5}{114}$