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

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

= 38 - (-15)

= 53

 7+(-12+43)-[ 2+(19-34)]

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

= 7 +   32 - [ 2 + ( -15 ) ]

= 7 + 32 - ( - 13 )

= 39 - ( - 13 )

= 52

7 + (-12 + 43) - [ 2 + (19 - 37) ]

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

= 38 - (-13)

= 51

52 nhé 51 là sai

\(\Rightarrow7+31-\left[2+\left(-15\right)\right]\)

\(\Rightarrow7+31-\left(-13\right)=7+31+13=20+31=51\)

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

\(=7+31-\left[2+\left(-15\right)\right]\)

\(=7+31-\left(-13\right)\)

\(=38+\left(-13\right)\)

\(=25\)

a, 25+ ( - 13 + 8 )

= 25+ ( -5 ) = 20

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

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

= 7 + 31 - ( - 13 )

= 38 - ( - 13 )

= 51

tk cho mk nha

7+(-12+ 43)- [2+(19- 34)]=7+31- [2+(-15)]

=7+31-(-13)

=38-(-13)=51

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

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

=7+31-(-13)

=38-(-13)

=51

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

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

=7+31-(-13)

=38-(-13)

=51

a)25+(-13+8)

=25+(-5)=20

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

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

=7+31-(-13)

=25

a)25-13+8=20

b)7-12+43-2+19-34=21

a) 25-13+8=20

b)7-12+43-2-19+34=51

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

=7-12+43-2-19+34

=(7+43)-(12+2)-19+34
=50-14-19+34

=36-19+34

=17+34

=51