1) = (8/31 + 23/31)+ ( -12/25+-13/25) = 1 + (-1) = 0
2) = 1/2 +3/4 -3/4 + 4/5 = 1/2 +4/5 = 13/10

3)= ( 7/3 x 15/21) x ( -5/2 x 4/-5 ) = ( 7/3 x 5/7 ) x 2 = 5/3 x 2 = 10/3

4) = 1/4 + 3/4 x -7/6 = 1/4 + -7/8 = -5/8

5)= 3/29 x 29/3 - 1/5 x 29/3 = 1 x 29/15 = 29/15

6)= 5/7 x ( 5/11 + 2/11 - 14/11) = 5/7 x -7/11 = -5 /11 

7) = 11/12 x -1/8 + 11/12 x -3/16  - 11/12 = 11/12 x ( -1/8 + -3/16 - 1) = 11/12 x -21/16 = -77/64 ( mk ko chắc , bạn ấn máy tính để thử lại )

8) = 203/20 - 7/4 + 41/13 = 198/20 + 41/13 = 99/10 + 41/13 = 1697/130 ( câu này cứ lỏ lỏ kiểu gì ý :v ) 

1) = (8/31 + 23/31)+ ( -12/25+-13/25) = 1 + (-1) = 0
2) = 1/2 +3/4 -3/4 + 4/5 = 1/2 +4/5 = 13/10

3)= ( 7/3 x 15/21) x ( -5/2 x 4/-5 ) = ( 7/3 x 5/7 ) x 2 = 5/3 x 2 = 10/3

4) = 1/4 + 3/4 x -7/6 = 1/4 + -7/8 = -5/8

5)= 3/29 x 29/3 - 1/5 x 29/3 = 1 x 29/15 = 29/15

6)= 5/7 x ( 5/11 + 2/11 - 14/11) = 5/7 x -7/11 = -5 /11 

7) = 11/12 x -1/8 + 11/12 x -3/16  - 11/12 = 11/12 x ( -1/8 + -3/16 - 1) = 11/12 x -21/16 = -77/64 ( mk ko chắc , bạn ấn máy tính để thử lại )

8) = 203/20 - 7/4 + 41/13 = 198/20 + 41/13 = 99/10 + 41/13 = 1697/130 ( câu này cứ lỏ lỏ kiểu gì ý :v ) 

\(=\dfrac{-3}{4}-\dfrac{1}{2}-\dfrac{3}{4}+\dfrac{5}{8}=\dfrac{-6}{4}+\dfrac{5}{8}-\dfrac{1}{2}=-2+\dfrac{5}{8}=\dfrac{-16+5}{8}=-\dfrac{11}{8}\)

\(=\dfrac{2}{3}+\dfrac{1}{5}-\dfrac{2}{3}-4\)

\(=\dfrac{1}{5}-4=\dfrac{-19}{5}\)

\(a,\left(31\dfrac{6}{13}+5\dfrac{9}{41}\right)-36\dfrac{6}{13}\\ =\left(31-36\right)+\left(\dfrac{6}{13}-\dfrac{6}{13}\right)+5\dfrac{9}{41}\\ =-5+0+5\dfrac{9}{41}\\ =\left(-5+5\right)+\dfrac{9}{41}=\dfrac{9}{41}\)

\(b,\dfrac{5}{3}+\left(-\dfrac{2}{7}\right)-\left(-1,2\right)\\ =\dfrac{5}{3}-\dfrac{2}{7}+\dfrac{6}{5}\\ =\dfrac{5.35-2.15+6.21}{105}=\dfrac{271}{105}\\ c,0,25+\dfrac{3}{5}-\left(\dfrac{1}{8}-\dfrac{2}{5}+1\dfrac{1}{4}\right)=\dfrac{1}{4}+\dfrac{3}{5}-\dfrac{1}{8}+\dfrac{2}{5}-1\dfrac{1}{4}\\ =\left(-1\dfrac{1}{4}+\dfrac{1}{4}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)-\dfrac{1}{8}=-1+1-\dfrac{1}{8}=-\dfrac{1}{8}\)

a) (31 6/13 + 5 9/41) - 36 6/13

= 409/13 + 214/41 - 474/13

= (409/13 - 474/13) + 214/41

= -5 + 214/41

= 9/41

b) 5/3 + (-2/7) - (-1,2)

= 5/3 - 2/7 + 6/5

= 29/21 + 6/5

= 271/105

c) 0,25 + 3/5 - (1/8 - 2/5 + 1 1/4)

= 1/4 + 3/5 - 1/8 + 2/5 - 5/4

= (1/4 - 5/4) + (3/5 + 2/5) - 1/8

= -1 + 1 - 1/8

= -1/8

Giải:

1) (-8/13:3/7+-5/13:3/7).(-4)³.|-3|/7

=[7/3.(-8/13+-5/13)].-192/7

=[7/3.(-1)].-192/7

=-7/3.-192/7

=64

2) 75%-(5/2+5/3)+(-1/2)²

=3/4-25/6+1/4

=(3/4+1/4)-25/6

=1-25/6

=-19/6

Chúc bạn học tốt!

1) \(\left(\dfrac{-8}{13}:\dfrac{3}{7}+\dfrac{-5}{13}:\dfrac{3}{7}\right).\dfrac{\left(-4\right).|-3|}{7}\)

  = \(\left[\left(\dfrac{-8}{13}+\dfrac{-5}{13}\right):\dfrac{3}{7}\right].\dfrac{-64.3}{7}\)

  = \(\left[-1:\dfrac{3}{7}\right].\dfrac{-192}{7}\)

  = \(\dfrac{-7}{3}.\dfrac{-192}{7}\)

  =       \(64\)

2)  \(75\%-\left(\dfrac{5}{2}+\dfrac{5}{3}\right)+\left(-\dfrac{1}{2}\right)^2\)

  = \(\dfrac{3}{4}-\dfrac{25}{6}+\dfrac{1}{4}\)

  = \(\left(\dfrac{3}{4}+\dfrac{1}{4}\right)-\dfrac{25}{6}\)

  =          \(1-\dfrac{25}{6}\)

  =            \(\dfrac{-19}{6}\)

Chúc bạn học tốt !

b: =12+5/14-3-5/7-5-5/14

=4-5/7

=28/7-5/7=23/7

c: =(-2/5-11/10)+(7/11-7/11)

=-4/10-11/10=-15/10=-3/2

\(a,\dfrac{5}{9}\cdot\dfrac{7}{13}+\dfrac{5}{9}\cdot\dfrac{8}{13}-\dfrac{5}{13}\cdot\dfrac{2}{9}\)

\(=\dfrac{5}{9}\cdot\dfrac{7}{13}+\dfrac{5}{9}\cdot\dfrac{8}{13}-\dfrac{2}{13}\cdot\dfrac{5}{9}\)

\(=\dfrac{5}{9}\cdot\left(\dfrac{7}{13}+\dfrac{8}{13}-\dfrac{2}{13}\right)\)

\(=\dfrac{5}{9}\cdot\dfrac{14}{13}\)

\(=\dfrac{70}{117}\)

\(d,\dfrac{1}{2}+\dfrac{-2}{3}+\dfrac{1}{6}+\dfrac{-2}{5}\)

\(=\left(\dfrac{1}{2}+\dfrac{-2}{3}+\dfrac{1}{6}\right)+\dfrac{-2}{5}\)

\(=0+\dfrac{-2}{5}\)

\(=\dfrac{-2}{5}\)

a: =-21/36-3/36=-24/36=-2/3

b: =43/12*1/2+5/24=43/24+5/24=2

c: =8/9+1/9=1

e: =1-1/4+1/4-1/7+...+1/97-1/100

=1-1/100=99/100

a) \(=\left(13\dfrac{2}{7}+2\dfrac{5}{7}\right):\left(-\dfrac{8}{9}\right)\)

\(=16:\dfrac{-8}{9}=\dfrac{-8\cdot\left(-2\right)\cdot9}{-8}=-18\)

b) 

\(=\left(\dfrac{-6}{11}\cdot\dfrac{11}{-6}\right)\cdot\dfrac{7\cdot10\cdot\left(-2\right)}{10}\)

\(=-14\)

c) \(=\dfrac{-1}{2}\cdot\dfrac{4}{3}\cdot\dfrac{-7}{2}\)

\(=\dfrac{-1\cdot2\cdot2\cdot\left(-7\right)}{2\cdot3\cdot2}=\dfrac{7}{3}\)

1, \(\dfrac{-3}{5}:\dfrac{7}{5}-\dfrac{3}{5}:\dfrac{7}{5}+2\dfrac{3}{5}\)

\(=\left(\dfrac{-3}{5}-\dfrac{3}{5}\right):\dfrac{7}{5}+\dfrac{13}{5}\)

\(=\dfrac{-6}{5}:\dfrac{7}{5}+\dfrac{13}{5}\)

\(=\dfrac{-6}{7}+\dfrac{13}{5}\\ =\dfrac{61}{35}\)

2, \(0,75-\left(2\dfrac{1}{3}+0,75\right)+3^2\cdot\left(-\dfrac{1}{9}\right)\)

\(=0,75-\dfrac{37}{12}+9\cdot\left(-\dfrac{1}{9}\right)\)

\(=-\dfrac{7}{3}+\left(-1\right)\\ -\dfrac{10}{3}\)

a. 5/6

b. -6/7

c. 2/3

d. 2/9

e. -63/325

g. 43/20

a. 1/12 + 3/4

= 1/12+ 9/12

= 10/12 = 5/6

b. -4/7. 1 1/2

= -4/7. 3/2

= -6/7

c. 7/9+ ( 2/3 + -7/9)

= 7/9 + -1/9

= 8/9 = 2/3

d. 2/3 - 1/3 : 3/4

= 2/3 - 4/9

= 6/9 - 4/9

= 2/9

e. -7/25 . 11/13+ - 7/25. 2/13

=-77/ 325+ -14/ 325

= - 7/25

g. 2 2/5 . 0,25- ( 11/20+ 75%) : 13/5

= 12/5 . 1/4 - ( 11/20 + 3/4) : 13/5

= 12/5 . 1/4 - 13/10 : 12/ 5

= 3/5 - 13/24

= 7/120

lm đại vậy thôi nha hơi lâu vì mik bị lag nên phải làm lại