解: 19×16+19×84104×25
=19(16+84104×25)
=19(16+84104×100/4)
=19(16+21026×100 )
=19(16+2102600 )
=19×2102616
=(20-1)×2102616
= 20 ×2102616 -2102616
=42052320-2102616
=39949704
19×16+19×84
=19x(16+84)
=19x100
=1900
104×25
=(100+4)x25
=100x25+4x25
=2500+100
=2600