(1)128+306÷17×9
=128+18×9
=128+162
=290;
(2)25×33×4×2
=25×4×2×33
=100×2×33
=200×33
=6600;
(3)156+6.2-15.6+6.2
=156-15.6+(6.2+6.2)
=140.4-12.4
=128;
(4)70-29.6-10.4
=70-(29.6+10.4)
=70-40
=30;
(5)283×5+17×5
=(283+17)×5
=300×5
=1500;
(6)43×102
=43×(100+2)
=43×100+43×2
=4300+86
=4386.