Đáp án:
(−5)+(−248)=−253(-5)+(-248)=-253
(−23)+105=82(-23)+105=82
80+(−220)=−14080+(-220)=-140
19+(23–33)19+(23–33)
=19+23−33=19+23-33
=42−33=42-33
=9=9
(−123)+(−13)+(−7)(-123)+(-13)+(-7)
=(−123)+[(−13)+(−7)]=(-123)+[(-13)+(-7)]
=(−123)+(−20)=(-123)+(-20)
=(−143)=(-143)
(−37)+(−15)=−52(-37)+(-15)=-52
6–(8–17)6–(8–17)
=6−8+17=6-8+17
=(−2)+17=(-2)+17
=15=15
99–[109+(−9)]99–[109+(-9)]
=99−100=99-100
=−1=-1
Giải thích các bước giải: