题目

计算: (1) (-2000 )+(-1999 )-(-4000 )-(+1 ); (2) (-5)×4 +7×(-4.4)-(-12)÷ +4 ; (3) (-5)2× +32÷ × . 答案: 解:原式= −2000−56−1999−23+4000+34−32 = −2000−1999+4000−56−23+34−32 = 1−94 =﹣ 54 ; 解:原式= −5×4.4+(−7)×4.4+12×4.4+4.4 = (−5−7+12+1)×4.4 =4.4; 解:原式= 25×(−35)+32×(−14)×(−54) = −15+10 =﹣5.
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