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

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

\(a.\left[-\dfrac{6}{11}.\dfrac{11}{-6}\right].\dfrac{7}{10}.\left(-20\right)=1.7.\left(-2\right)=-14\)

\(b.\dfrac{-1}{2}:\dfrac{3}{4}.\dfrac{-7}{2}=\dfrac{7}{4}:\dfrac{3}{4}=\dfrac{7}{3}\)

\(c.\dfrac{93}{7}:-\dfrac{8}{9}+\dfrac{19}{7}:\dfrac{-8}{9}=\left(\dfrac{93}{7}+\dfrac{19}{7}\right):-\dfrac{8}{9}=\dfrac{-9}{8}.\dfrac{112}{7}=-18\)

a: 60,7+25,5-38,7

=60,7-38,7+25,5

=22+25,5

=47,5

b: \(1,3+5,2\cdot\left(-2\right)\)

=1,3-10,4

=-9,1

c: -3,7+8,1+6,7

=8,1+3

=11,1

d: \(12,65+\left(-2,35\right)=12,65-2,35=10,3\)

e: \(\left(-0,4\right)\cdot\left(-0,5\right)\cdot\left(-0,8\right)=-0,4\cdot0,5\cdot0,8=-0,2\cdot0,8=-0,16\)

f: \(3,58\cdot24,45+3,58\cdot75,55\)

\(=3,58\cdot\left(24,45+75,55\right)\)

\(=3,58\cdot100=358\)

g: 2,07+(-7,36)-(-8,97)+1,03-7,64

=2,07-7,36-7,64+8,97+1,03

=2,07-15+10

=2,07-5

=-2,93

h: 4,35-(2,67-1,65)+(3,45-6,33)

=4,35-2,67+1,65+3,45-6,33

=6+3,45-9

=3,45-3

=0,45

i: (0,36-36):(3,8+0,2)

=-35,64:4

=-8,91

j: 1,456:0,28+4,5x0,8

=5,2+3,6

=8,8

khó nhìn quá e chỉnh lại đi nha

(-5).8.(-2).(-125)

=[(-5).(-2)].[8.(-125)]

=10.(-1000)

=-10000

Thực hiện phép tính ( bằng cách hợp lí nếu có thể ) 

A. 2/3 - (- 1/4)+3/5-(+7/45)-(-5/9)+1/12+1/39 

B. 6.(-2/3)^2 - 3(-2/3)^2 - 2 : (-3/2)+4

a) 2/9 - (1/20 + 2/9)

= 2/9 - 1/20 - 2/9

= (2/9 - 2/9) - 1/20

= 0 - 1/20

= -1/20

b) -3/14 + 2/13 + (-25/14) + (-15/13)

= (-3/14 - 25/14) + (2/13 - 15/13)

= -2 - 1

= -3

c) -3/11 + 11/8 - 3/8 + (-8/11)

= (-3/11 - 8/11) + (11/8 - 3/8)

= -1 + 1

= 0

d) 3/8 + (-1/4) - (7/12 - 1/6)

= 1/8 - 5/12

= -7/24

e) (1/3 + 12/67 + 13/41) - (79/67 - 28/41)

= 1/3 + 12/67 + 13/41 - 79/67 + 28/41

= 1/3 + (12/67 - 79/67) + (13/41 + 28/41)

= 1/3 - 1 + 1

= 1/3

a, (-20) + 16 + (-34) + 20 = [(-20) + 20] + [16 + (-34)] = 0 + (-18) = (-18) b, 12 + 3.[39 - (5 - 2)²] = 12 + 3.[39 - 3²] = 12 + 3.[39 - 9] = 12 + 3.30 = 12 + 90 = 102

\(\dfrac{4}{5}\)+\(\dfrac{-5}{4}\)=\(\dfrac{0}{4}\)

\(\dfrac{-1}{3}\)+\(\dfrac{2}{5}-\dfrac{5}{6}\)=\(\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}\)=\(\dfrac{-23}{30}\)

\(\dfrac{2}{3}-\dfrac{5}{7}.\dfrac{14}{25}\)=\(\dfrac{2}{3}-\dfrac{2}{5}\)=\(\dfrac{10}{15}-\dfrac{6}{15}\)=\(\dfrac{4}{15}\)

Gigachad cảm ơn bạn sai rồi

\(-\frac{2}{3}+\frac{1}{5}.\frac{-10}{7}\\ =-\frac{2}{3}+\frac{1.-10}{5.7}\\ =-\frac{2}{3}+\frac{-2}{7}\\ =-\frac{14}{21}+\frac{-6}{21}\\ =-\frac{20}{21}\)

=\(\frac{-2}{3}+\frac{1}{5}.\frac{-10}{7}\)

=\(\frac{-2}{3}+\frac{-2}{7}\)

=\(\frac{-20}{21}\)