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Giải thích các bước giải:
a)-(168+325)+(168 + 425)
= -168-325+168+425
= (168-168) + (425-325)
= 0 + 100 = 100
b)(38-276)+(38-65+276)
= 38-276+38-65+276
= (38 + 38)-65+(276-276)
=68-65+0=3
c)(269+135)+(-327-169)-(135-27)
= 269 + 135 - 327 - 169 - 135 + 27
= (269-169)+(135-135)+(27-327)
= 100+0-300= -200
d)271-[(-43)+271-(-17)]
=271-(271-43+17)
=271-271+(43-17)
=0+26=26
e)-144-[29-(+144)-(+144)]
=-144-(29-144-144)
=-144-29+144+144
=(144-144)+(144-29)
=0+115=115
f)29.(19-13)-19.(29-13)
= 29.19-29.13-(19.29-19.13)
= 29.19-29.13-19.29+19.13
= (29.19-19.29)+13.(19-29)
= 0+13.(-10)=-130
g)31.(-18)+31.(-81)-31
= 31.(-18)+31.(-81)+31.(-1)
= 31.(-18-81-1)
= 31.(-100) =-3100
a)(a+b-c)-(b-c+d)
= a+b-c-b+c-d
=(b-b)+(c-c)+a-d
= a-d
b)-(a-b+c)+(a-b+d)
= -a+b-c+a-b+d
= (a-a)+(b-b)+d-c
= d-c
c)(a+b)-(-a+b-c)
= a+b+a-b+c
=2a + c+ (b-b)
= 2a +c