分析:(1)把除法改為乘法,運用乘法分配律的逆運算簡算;
(2)先算小括號內(nèi)的,再算中括號內(nèi)的乘法,然后算中括號內(nèi)的減法,最后算括號外的除法;
(3)先算下括號內(nèi)的,再算中括號內(nèi)的乘法,然后算中括號內(nèi)的減法,最后算括號外的除法;
(4)根據(jù)數(shù)字特點,把原式變?yōu)?111×2×0.27+1111×6×0.09-1111×3×0.16,運用乘法分配律的逆運算簡算.
解答:解:(1)
÷23+
×
+
,
=
×
+
×
+
,
=(
+
+1)×
,
=2×
,
=
;
(2)[5-(11.9-8.4)×
1]÷130%,
=[5-3.5×
]÷130%,
=[5-
×
]÷130%,
=[5-
]÷
=
×
,
=
;
(3)3
÷[5
-4.5×(20%+
)],
=3
÷[5
-4.5×(
+
)],
=3
÷[5
-4.5×
],
=3
÷[5
-
],
=
÷
,
=1;
(4)2222×
+6666×0.09-3333×0.16,
=1111×2×0.27+1111×6×0.09-1111×3×0.16,
=1111×(0.54+0.54-0.48),
=1111×0.6,
=666.6.
點評:考查了四則混合運算,注意運算順序和運算法則,靈活運用所學的運算定律簡便計算.