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Giải thích các bước giải:
Bài 1
1)2155-(174-2155)=2155-74+2155=4236
2)-25.72+25.21-49.25=25.(-72)+25.21-49.25=25.(25+49-72)=25.2=50
3)35(14-23)-23(14-35)=35.(-9)-23.(-9)=(-9).(35-23)=-9.12=-108
5-25.21+25.72+49.25=25.(-21)+25.72+49.25=25.(49+72-21)=25.100=2500
6)27(13-16)-16(13-27)=27.(-3)-16.(-14)=-81-224=-305
7)=-1911-1234+1911=(1911-1911)-1234=-1234
9)=16.(-39.2)+16(-22)=16.(-22-78)=16.(-100)=-1600
10)-1945-(567-1945)=-1945-567+1945=-567
11)=184.(33+67)=184.100=18400
12)=22(-36.2)+22.(-28)=22.(-72-28)=-2200