a.      19 + 18 + 17 + 16 + 14 + 21 + 22 +  23 + 24 + 26

= (19 + 21) + (18 + 22) + (17 + 23) + (16 + 24) + (14 + 26)

= 40 + 40 + 40 + 40 + 40

= 40 x 5

= 200

a, 3.7.23 - 21.(-17)

= 21.23  + 21.17

= 21.(23 + 17)

= 21.40

= 840

b, 7.6.3 - 7.[(-34) + 18)]

= 7.18 - 7.18 + 34.7

= 34.7

= 238

c, 71.64 + 32.(-7) - 13.32

= 71. 32 . 2 - 7.32 - 32. 13

= 32.(71.2 - 7 - 13)

= 32. (142 - 20)

= 32.122

=  3904

d, 13.(23 - 17) - 13.(23 + 17)

= 13.23 - 13.17 - 13.23 - 13.17

= (13.23 - 13.23) - (13.17 + 13.17)

= - 2.13.17

= - 26.17

= -442

e, (29 - 9).(-9) + (-13 - 7).21

= 20.(-9) - 20.21

= -20.(9 + 21)

= -20.30

= - 600

= 23 . 41 + 59 . 23

= 23 . ( 41 + 59 )

= 23 . 100

= 2300

HỌC TỐT !

Tổng của dãy là:

23.41 + 59 .23

=23. (41+59)

=23.100

= 2300

=>= 23.41+23.59

=23.(41+59)

=23.100

=2300

chúc học tốt nha tv thân yêu của team

a) \(\frac{7}{18}+\frac{4}{23}+\frac{11}{18}+\frac{19}{23}\)

\(=\left(\frac{7}{18}+\frac{11}{18}\right)+\left(\frac{4}{23}+\frac{19}{23}\right)\)

\(=1+1\)

\(=2\)

b) \(\frac{19}{15}+\frac{31}{23}-\frac{4}{15}-\frac{8}{23}\)

\(=\left(\frac{19}{15}-\frac{4}{15}\right)+\left(\frac{31}{23}-\frac{8}{23}\right)\)

\(=1+1\)

\(=2\)

ủng hộ tớ nha

a) (7/18+11/18)+(4/23+19/23)

=18/18+23/23

=1+1

=2

b)=2

\(a,b=2\)

TL: 

8/15 x 5/6 = 40/90 = 4/9 

41/20 x 3/4 = 123/80 

(11/23 + 9/23) + (18/23 + 2/23) = 20/23 + 20/23 = 40/43 

HT

\(\left(\frac{2}{3}\times\frac{4}{5}\right)\times\frac{5}{6}\) = \(\frac{2}{3}\times\frac{4}{5}\times\frac{5}{6}\)=\(\frac{2\times4\times5}{3\times5\times6}\)=\(\frac{2\times4\times5}{3\times5\times2\times3}\)=\(\frac{4}{9}\)

\(\frac{11}{23}+\frac{2}{23}+\frac{9}{23}+\frac{18}{23}\)=\(\frac{\left(11+9\right)+\left(18+2\right)}{23}\)=\(\frac{20+20}{23}\)=\(\frac{40}{23}\)

\(\frac{27}{12}+\frac{17}{6}-\frac{25}{36}-\frac{15}{6}\)=\(\left(\frac{27}{12}-\frac{25}{36}\right)+\left(\frac{17}{6}-\frac{15}{6}\right)\)=\(\frac{14}{9}+\frac{2}{6}\)=\(\frac{17}{9}\)

/HT\

Nhập các bạn toàn bắt tớ làm à ngu gò mà làm

a) \(...=-\dfrac{12}{46}-\dfrac{15}{21}+\dfrac{3}{7}-\dfrac{7}{23}\)

\(=-\dfrac{12}{46}-\dfrac{7}{23}-\dfrac{15}{21}+\dfrac{3}{7}\)

\(=-\dfrac{6}{23}-\dfrac{7}{23}-\dfrac{5}{7}+\dfrac{3}{7}\)

\(=-\dfrac{13}{23}-\dfrac{2}{7}\)

\(=-\dfrac{13.7}{23.7}-\dfrac{2.23}{23.7}\)

\(=-\dfrac{91}{161}-\dfrac{46}{161}=-\dfrac{137}{161}\)

b) \(...=-21+\dfrac{7}{9}-\dfrac{3}{17}+\dfrac{25}{9}\)

\(=-21-\dfrac{3}{17}+\dfrac{7}{9}+\dfrac{25}{9}\)

\(=-21-\dfrac{3}{17}+\dfrac{32}{9}\)

\(=-\dfrac{3213}{153}-\dfrac{27}{153}+\dfrac{544}{153}=-\dfrac{2696}{153}\)

1. 

= 10 000 - 29 x 11

= 10 000 - 319

= 9681

2.

= ( 3/7 + 4/7 ) + ( 4/9 + 5/9 )

= 1 + 1

= 2

giúp mk với

(23/11+10/11) + 1/5

= 3 + 1/5 

= 16/5

    \(\dfrac{23}{11}+\left(\dfrac{1}{5}+\dfrac{10}{11}\right)\)

\(=\dfrac{23}{11}+\dfrac{1}{5}+\dfrac{10}{11}\)

\(=\left(\dfrac{23}{11}+\dfrac{10}{11}\right)+\dfrac{1}{5}\)

\(=3+\dfrac{1}{5}=\dfrac{3}{1}+\dfrac{1}{5}\)

\(=\dfrac{15}{5}+\dfrac{1}{5}\) \(=\dfrac{15+1}{5}=\dfrac{16}{5}\)