a) -321  + (-29) - 142  - (-72)

= [-321  +(-29)]+ [(-142)  + 72]

= [-(321 + 29)] + [- (142 - 72)]

= (-350) + (-70)

= -(350 + 70)

= -420

b) 214 - (-36) + (-305)

= 214 + 36 - 305

= 250 - 305

= -(305 - 250)

= -55.

a, -321 + (-29 ) - 142 - (-72) = -321 - 29 - 142 + 72 = -420.

b, 214 - (-36) + (-305) = 214 + 36 - 305 = -55.

c, 232 - (581 + 132 - 331) = 232 - 581 - 132 + 331 = -150.

d, [ 12+ (-57)] - [-57 -  (-12) = 12 - 57 + 57 - 12 = 0.

a) \(-321+\left(-29\right)-142-\left(-72\right)\)

\(=-321-29-142+72\)

\(=-492+72\)

\(=-420\)

b) \(214-\left(-36\right)+\left(-305\right)\)

\(=214+36-305\)

\(=250-305\)

\(=-55\)

=-350-70

=-420

-420

-321 + (-29) - 142 - (-72)

=[(-321) + (-29)] - (142 + 72)

=       -350          -       214

= -564( cứ thấy sai sai:))

`-321+(-29)-142-(-72)`

`=-321-29-142+72`

`=-(321+29)-(142-72)`

`=-350-70`

`=-420`

\(-321+\left(-29\right)-142-a\left(-72\right)\)

\(=\left(-321-29-142\right)+72a\)

\(=-492+72a\)

lấy nháp ra tính đi em !

214 - (-36) + (-305) 

= 214 + 36 – 305

= 250 – 305

= - (305 – 250) 

= -55

214 - (-36) + (-305) 

= 214 + 36 – 305

= 250 – 305

= - (305 – 250) 

= -55

tính : 3/17 . 6/29 - 3/17 . 35/29 + 2022 3/17
b, 5/6-(1/3+1/2). 20%
c,9.5+(-13,2)+12,5+(-0,8)
 

214+[120-(214+120)]

=214+120-(214+120)

=214+120-214-120

=(214-214)+(120-120)

=0+0=0

(-321)-[(-321+35)-235]

=(-321)-(-321+35)+235

=(-321)+(-321-35)-235

=-321-(-321) +(235-35)

=0+200

=200

(18+29)+(158-29-18)

=18+29+158-29-18

=(18-18)+(29-29)+158

=0+0+158

=158

(13-135+49)-(13+49)

=13-135+49-13-49

=(13-13)+(49-49)-135

=0-135

= -135

25+(-13+8)

=25+(-5)

=20

7+(-12+43)-[2+(19-34)]

=7+31-[2+(-15)]

=7+31-(-13)

=38+(-13)

=25

nhiều quá, mk phụ chút thôi

1.a)214+[120-(214+120)=214+120-214-120=(214-214)+(120-120)=0+0=0

b)(-321)-[(-321+35)-235]=(-321)+321-35+235=[(-321)+321]+(235-35)=0+200=200

2.a)(18+29)+(158-29-18)=18+29+158-29-18=(18-18)+(29-29)+158=0+0+158=158