Tính hợp lí nhất
1, 2155– (174 + 2155) + (-68 + 174) 2, -25 . 72 + 25 . 21 – 49 . 25 3, 35(14 –23) – 23(14–35) 4, 8154– (674 + 8154) + (–98 + 674) 5, – 25 . 21 + 25 . 72 + 49 . 25 6, 27(13 – 16) – 16(13 – 27)
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7, –1911 – (1234 – 1911) 8, 156.72 + 28.156 9, 32.( -39) + 16.( –22) 10, –1945 – ( 567– 1945) 11, 184.33 + 67.184 12, 44.( –36) + 22.( –28)
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1) \( 2155 – (174 + 2155) + (-68 + 174) = -68\)
2) \(-25 . 72 + 25 . 21 – 49 . 25=-2500\)
3) \(35.(14 –23) – 23.(14–35)=168\)
4) \(8154 – (674 + 8154) + (–98 + 674)=-98\)
5) \(25.21+25.72+49.25=2399\)
6) \(27.(13-16)-16.(13-27)=143\)
7) \(–1911 – (1234 – 1911) =-1234\)
8) \(156.72 + 28.156 =15600\)
9) \(32.(-39)+16.(-22)=-1600\)
10) \(–1945 – ( 567– 1945) =-567\)
11) \(184.33 + 67.184 =18400\)
12) \(44.( –36) + 22.( –28)=-2200\)