(1)
÷[(
-
)×
](2)4×0.8×2.5×12.5
(3)4.26+2.4+
+
(4)(
+
×
)÷
(5)56×
(6)0.65×14+87×65%-65%解:(1)
÷[(
-
)×
]=
÷[(
-
)×
],=
÷[
×
],=
÷
,=
×15,=5;
(2)4×0.8×2.5×12.5
=(4×2.5)×(0.8×12.5),
=10×10,
=100;
(3)4.26+2.4+
+
=4.26+2.4+1.6+1.375,
=4.26+(2.4+1.6)+1.375,
=4.26+4+1.375,
=9.635;
(4)(
+
×
)÷
=(
+
)×
,=(
+
)×
,=
×
,=
;(5)56×
=(57-1)×
,=57×
-
,=2-
,=1
;(6)0.65×14+87×65%-65%
=0.65×14+87×0.65-0.65,
=(14+87-1)×0.65,
=100×0.65,
=65.
分析:算式(1)、(4)根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的;
算式(2)可根据乘法交换律及结合律计算;
算式(3)可将式中分数化为小数后根据加法结合律计算;
算式(5)可将56变为57-1后根据乘法分配律计算;
算式(6)可根据乘法分配律计算.
点评:完成本题要认真分析式中数据的特点及内在联系,然后选择合适的方法计算.