(1)27+[0.3×(8-
)](2)2012÷
-3
×2012(3)[1.9+19%×(5.8-4
)]+(53×
+30.6×0.25)解:(1)27+[0.3×(8-
)],=27+[
×
],=27+
,=27
;(2)2012÷
-3
×2012,=2012×
-3
×2012,=2012×(
-3
),=2012×2,
=4024;
(3)[1.9+19%×(5.8-4
)]+(53×
+30.6×0.25),=[1.9×(5.8-4.8+1)]+(53×
+30.6×
),=(1.9×2)+(53+30.6)×
,=3.8+83.6×
,=3.8+20.9,
=24.7.
分析:(1)先算小括号内的,再算中括号内的,最后算括号外的;
(2)把除法改为乘法,运用乘法分配律简算;
(3)把19%和4
化为小数,把0.25化为分数,两个括号都可运用乘法分配律简算.点评:考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.