5-
-
71×99
0.625×0.5+
+
×62.5%8.37-3.25-(1.37+1.75)
45×(
+
-0.6)0.25×48.解:(1)5-
-
,=5-(2
),=5-3,
=2;
(2)71×99,
=71×(100-1),
=71×100-71,
=7100-71,
=7029;
(3)0.625×0.5+
+
×62.5%,=0.625×0.5+0.625+0.5×0.625,
=0.625×(0.5+0.5+1),
=0.625×2,
=1.25;
(4)8.37-3.25-(1.37+1.75),
=8.37-1.37-(3.25+1.75),
=7-5,
=2;
(5)45×(
+
-0.6),=45×
+45×
-45×0.6,=35+12-27,
=20;
(6)0.25×48,
=(0.25×4)×12,
=1×12,
=12.
分析:(1)5-
-
,应用减法的运算性质进行简算;(2)71×99,转化为71×(100-1),应用乘法分配律进行简算;
(3)0.625×0.5+
+
×62.5%,把
和62.5%都化成小数,再应用乘法分配律进行简算;(4)8.37-3.25-(1.37+1.75),应用减法的运算性质进行简算;
(5)45×(
+
-0.6),应用乘法分配律进行简算;(6)0.25×48转化为0.25×4×12,应用乘法结合律进行简算.
点评:此题考查的目的是灵活运用运算定律、运算性质对整数、小数、分数四则混合运算进行简便计算.