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(1)312×4+188×4=(312+188)×4=500×4=2000;(

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(1)312×4+188×4
=(312+188)×4
=500×4
=2000;

(2)25×33×4
=25×4×33
=100×33
=3300;

(3)101×87
=(100+1)×87
=100×87+1×87
=8787;

(4)4000÷25-13×12
=160-156
=4;

(5)64-(7.2+5.9)
=64-13.1
=50.9;

(6)(75+240)÷(20-5)
=315÷15
=21;

(7)85.7-(15.3-4.8)
=85.7-10.5
=75.2;

(8)51.27-8.66-1.34
=51.27-(8.66+1.34)
=51.27-10
=41.27;

(9)10.75+0.4-9.86
=11.15-9.86
=1.29.