(9991×1999.1999+9991.9991×1999)÷2.0002
问题描述:
(9991×1999.1999+9991.9991×1999)÷2.0002
答
(9991×1999.1999+9991.9991×1999)÷2.0002
=(9991*1999*1.0001+9991*1.0001*1999)/2.0002=9991*1999(1.0001+1.0001)/2.0002
=9991*1999*2.0002/2.0002
=9991*1999
=9991*(2000-1)
=19982000-9991
=19972009
答
(9991×1999.1999+9991.9991×1999)÷2.0002=( 9991×1999×10001÷10000 + 9991×10001×1999÷ 10000)÷(10001×2÷10000)=( 9991×1999 + 9991×1999)÷2= 9991× 1999= 9991×2000 - 9991= 19982000 - 9...