Tính nhanh a) (-77 – 23) – (567 – 77) b) 7 – (-812 – 45) + (55 – 812) c) (-13) – [2022 – (23 +2011)] d) (72 – 56) – [(-123) + (-28+44)

0 bình luận về “Tính nhanh a) (-77 – 23) – (567 – 77) b) 7 – (-812 – 45) + (55 – 812) c) (-13) – [2022 – (23 +2011)] d) (72 – 56) – [(-123) + (-28+44)”

1. Đáp án:

   `a)=-590`

   `b)=107`

   `c)=-1`

   `d)=123`

   Giải thích các bước giải:

   Ta có :

   `a,(-77-23)-(567-77)`

   `=-77-23-567+77`

   `=(77-77)-(23+567)`

   `=0-590`

   `=-590`

   `———-`

   `b,7-(-812-45)+(55-812)`

   `=7+812+45+55-812`

   `=7+(812-812)+(55+45)`

   `=7+0+100`

   `=107`

   `———–`

   `c,(-13)-[2022-(23+2011)]`

   `=-13-(2022-23-2011)`

   `=-13-2022+23+2011`

   `=(23-13)+(2011-2022)`

   `=10+(-11)`

   `=-1`

   `———–`

   `d,(72-56)-[(-123)+(-28+44)]`

   `=72-56+123+28-44`

   `=(72+28)-(56+44)+123`

   `=100-100+123`

   `=0+123`

   `=123`

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2. a)

   (-77 – 23) – (567 – 77)

   =-77-23-567+77

   =(-77+77)+(-23-567)

   =0+-590

   =-590

   b)

   7 – (-812 – 45) + (55 – 812)

   =7+812+45+55-812

   =(812-812)+(45+55)+7

   =0+100+7

   =107

   c)

   (-13) – [2022 – (23 +2011)]

   =-13-(2022-2024)

   =-13-(-2)

   =-13+2

   =-11

   d)

   (72 – 56) – [(-123) + (-28+44)

   =72-56+123-28+44

   =(-56+44)-28+(72+123)

   =-12-28+195

   =-40+195

   =155

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