解:(1)486+899,
=500+900-14-1,
=1385;
(2)9000-271-729,
=9000-(271+729),
=9000-1000,
=8000;
(3)125×25×32,
=(125×8)×(25×4),
=1000×100,
=100000;
(4)86×33+86×66+86,
=86×(33+66+1),
=86×100,
=8600;
(5)7777×8+1111×4,
=1111×56+1111×4,
=1111×(56+4),
=1111×60,
=66660;
(6)(120+780÷130)×84-10000,
=(120+6)×84-10000,
=126×84-10000,
=10584-10000,
=584.
分析:(1)486+899,根據(jù)加法的運算性質進行簡算;
(2)9000-271-729,根據(jù)減法的運算性質進行簡算;
(3)125×25×32,把32分解為:8×4,再運用乘法的交換律和結合律進行簡算;
(4)86×33+86×66+86,運用乘法分配律進行簡算;
(5)7777×8+1111×4,將原式轉化為:1111×56+1111×4,再運用乘法分配律進行簡算;
(6)(120+780÷130)×84-10000,根據(jù)整數(shù)四則混合運算的順序,按照整數(shù)四則運算的計算法則進行簡算.
點評:此題考查的目的是掌握整數(shù)四則混合運算的順序及四則運算的計算法則,并且能夠靈活選擇簡便方法進行簡算.