| 计算下面各题,能用简便算法的用简便算法. (1)12.25-3.1+0.85-6.17; (2)1.9-1.9×0.9; (3)2.65×1.7+1.35×1.7; (4)2.98+6.5×(3.2-3.12). |
| (1)12.25-3.1+0.85-6.17 =(12.25+0.85)-(3.1+6.17) =13.1-9.27 =3.83 (2)1.9-1.9×0.9 =1.9×(1-0.9) =1.9×0.1 =0.19 (3)2.65×1.7+1.35×1.7 =(2.65+1.35)×1.7 =4×1.7 =6.8 (4)2.98+6.5×(3.2-3.12) =2.98+6.5×0.08 =2.98+0.52 =3.5 |
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