(1)425-83-17,
=425-(83+17),
=425-100,
=325;
(2)74×38+74×62,
=74×(38+62),
=74×100,
=7400;
(3)32×125,
=4×8×125,
=4×(8×125),
=4×1000,
=4000;
(4)99×35,
=(100-1)×35,
=100×35-35×1,
=3500-35,
=3465;
(5)526-(134+226),
=526-226-134,
=300-134,
=166;
(6)7.25+49.6+52.75,
=7.25+52.75+49.6,
=60+49.6,
=109.6.