(1)75×80%+24×
+0.8 (2)

(3)(1.875-1÷
)×
(4)(
-
)÷
.解:(1)75×80%+24×
+0.8,=75×0.8+24×0.8+0.8,
=(75+24+1)×0.8,
=100×0.8,
=80;
(2)
÷[
×(
-
)],=
÷[
×
],=
÷
,=
×
,=
;(3)(1.875-1÷
)×
,=(
-
)×
,=0;
(4)(
-
)÷
,=(
-
)×24,=
×24,=
.分析:(1)把百分数和分数化为小数,运用乘法分配律的逆运算简算;
(2)按运算顺序计算,先算小括号内的,再算中括号内的,最后算括号外的;
(3)通过计算,括号内的结果为0,因此得数为0;
(4)先算括号内的,再算括号外的.
点评:考查了四则混合运算,注意运算顺序,并灵活运用所学的运算定律简便计算.