(1)1375+450÷18×25 (2)(
)÷2
(3)3-112.5%+1
(4)7
(5)
(6)5
.解:(1)1375+450÷18×25 =1375+25×25
=1375+625
=2000;
(2)(
)÷2
=(

)×
=
×
-
×
=


=
;(3)3-112.5%+1

=3-1.125+1

=1
+1
=3
;(4)7

=7
×
-
×
=30-2
=28;
(5)
=[2
+(
-
)×1
]÷3
=[2
+
×
-
×
]÷3
=(
+
-
)×
=(

)×
=
×
-
×
=


=
;(6)5

=5
-5
=
.分析:(1)(3)(4)(5)(6)按照先算乘除再算加减的运算顺序计算;(2)可以用乘法分配律简算.
点评:乘法分配律是常用的简算方法,注意其变形后的使用.