求文档:(9991*1999.1999+1999*9991.9991)/2.0002
问题描述:
求文档:(9991*1999.1999+1999*9991.9991)/2.0002
(9991×1999.1999+1999×9991.9991)÷2.0002
答
(9991×1999.1999+1999×9991.9991)÷2.0002=(9991×1999×1.0001+1999×9991×1.0001)÷(2×1.0001)=2×1999×9991×1.0001÷(2×1.0001)=1999×9991=(2000-1)×9991=19982000-9991=19972009