简算:(9991*1999.1999+9991.9991*1999)/2.0002=

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简算:(9991*1999.1999+9991.9991*1999)/2.0002=简算:(9991*1999.1999+9991.9991*1999)/2.0002=简算:(9991*1999.19

简算:(9991*1999.1999+9991.9991*1999)/2.0002=
简算:(9991*1999.1999+9991.9991*1999)/2.0002=

简算:(9991*1999.1999+9991.9991*1999)/2.0002=
(9991*1999.1999+9991.9991*1999)/2.0002
=(9991*1999*1.0001+9991*1.0001*1999)/2.0002
=1.0001(9991*1999+9991*1999)/2.0002
=1.0001*2*9991*1999/2.0002
=9991*1999
=19972009

设9991=a,1999=b则原式=(a×1.0001b+1.0001a×b)÷2.0002=(1.0001ab+1.0001ab)÷2.0002=2.0002ab÷2.0002=ab=9991×1999=19972009