解题思路:(1)把0.9999拆成0.1111×9,然后再根据乘法分配律进行简算即可.
(2)设1+0.228-0.21=a,0.228-0.21=b,通过代入,即可求出问题的答案.
(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+0.228-0.21+0.2003)×(0.228-0.21)
=a×(b+0.2003)-(a+0.2003)×b
=ab+0.2003a-ab-0.2003b
=0.2003×(a-b)
=0.2003×1
=0.2003
点评:
本题考点: 小数的巧算.
考点点评: 完成此题,应仔细观察数据特点,采用巧妙的方法,解决问题.