75×27+19×25
=(25×3)×27+19×25
=25×(3×27)+19×25
=25×81+19×25
=25×(81+19)
=2500
75×27+19×25
=75×27+19×(100-75)
=75×27+19×100-19×75
=(27-19)×75+1900
=8×75+1900
=(4×2×25×3)+1900
=100×6+1900
=600+1900
=2500
3×25×27+19×25=25×(81+19)=2500
75×27+19×25
=<75+25>×19+<27-19>×25
=100×19+8×25
=1900+200
=2100