用简便方法计算 (1)0.9999×0.7+0.1111×2.7; (2)(1+0.228-0.21)×(0.228-0.21+0.2003)-(1+0.228-0.21+0.2003)×(0.228-0.21)
问题描述:
用简便方法计算
(1)0.9999×0.7+0.1111×2.7;
(2)(1+0.228-0.21)×(0.228-0.21+0.2003)-(1+0.228-0.21+0.2003)×(0.228-0.21)
答
(1)0.9999×0.7+0.1111×2.7=(0.1111×9)×0.7+0.1111×2.7=0.1111×6.3+0.1111×2.7=0.1111×(6.3+2.7)=0.1111×9=0.9999(2)设1+0.228-0.21=a,0.228-0.21=b,(1+0.228-0.21)×(0.228-0.21+0.2003)-(1...