(1)287×99,
=287×(100-1),
=287×100-287×1,
=28700-287,
=28413;
(2)372-(272+77),
=372-272-77,
=100-77,
=23;
(3)125×(80+8),
=125×80+125×8,
=10000+1000,
=11000;
(4)640÷(80×4),
=640÷320,
=2;
(5)767-252-148,
=767-(252+148),
=767-400,
=367;
(6)213×15+86×15+15,
=(213+86+1)×15,
=300×15,
=4500;
(7)268+199,
=268+100-1,
=368-1,
=367;
(8)125×4×8×25,
=(125×8)×(4×25),
=1000×100,
=100000;
(9)372-197+128,
=372+128-197,
=500-200+3,
=303.