Đáp án:
a,(3567-214)-3567
=3567-214-3567
=(3567-3567)-214
=-214
b,(-2017)-(28-2017)
=(-2017)-28+2017
=[(-2017)+2017]-28
=-28
c, -(269-357)+(269-357)
=-269+357+269-357
=(-269+269)+357-357
=0
d, (123+345)+(456-123)-[2017-(345)]
=123+345+456-123-2017+345
=(123-123)+(345+345+456-2017)
=-871