考點:整數(shù)、分數(shù)、小數(shù)、百分數(shù)四則混合運算
專題:運算順序及法則
分析:(1)把小數(shù)化為分數(shù),先算除法,然后從左往右依次運算.
(2)先算括號內(nèi)的,然后從左往右依次運算.
(3)運用乘法分配律簡算.
(4)把百分數(shù)和小數(shù)化為分數(shù),運用乘法分配律簡算.
(5)通過數(shù)據(jù)轉(zhuǎn)化,運用乘法分配律簡算.
(6)把百分數(shù)和小數(shù)化為分數(shù),先算小括號內(nèi)的,再算中括號內(nèi)的,最后算括號外的.
解答:
解:(1)1+0.45÷
-
=1+
×
-
=1+
-
=
(2)
÷(
-
)×
=
÷
×
=
×
×
=
(3)12×(
+
-
)
=12×
+12×
-12×
=3+2-4
=1
(4)78×
+23×25%-0.25
=78×
+23×
-
=(78+23-1)×
=100×
=25
(5)
×8+
×12
=
×5+
×12
=
×(5+12)
=
×17
=8
(6)[
-(0.5+25%)]÷
=[
-(
+
)]÷
=[
-
]÷
=
×
=
點評:此題考查了分數(shù)的四則混合運算,注意運算順序和運算法則,靈活運用所學(xué)的運算定律簡便計算.