考點(diǎn):整數(shù)、分?jǐn)?shù)、小數(shù)、百分?jǐn)?shù)四則混合運(yùn)算,運(yùn)算定律與簡便運(yùn)算
專題:運(yùn)算順序及法則,運(yùn)算定律及簡算
分析:(1)首先計(jì)算小括號(hào)里面的,然后計(jì)算小括號(hào)外面的即可;
(2)根據(jù)減法的性質(zhì)簡算即可;
(3)(6)首先計(jì)算小括號(hào)里面的,然后從左向右依次計(jì)算即可;
(4)首先計(jì)算小括號(hào)里面的,然后計(jì)算中括號(hào)里面的,最后計(jì)算中括號(hào)外面的即可;
(5)首先乘法分配律簡算即可.
解答:
解:(1)
×(
+
)
=
×=
(2)
÷(3-
-
)
=
÷[3-(
+
)]
=
÷[3-1]
=
÷2
=
(3)
×(
+
)÷6
=
×
÷6
=
(4)28-[(
-
)×2]
=28-[
×2]
=28-
=
27(5)(
-
)×
=
×
-
×
=1-
=
(6)(
+
)×5÷
=
×5×5=21
點(diǎn)評(píng):此題主要考查了整數(shù)、分?jǐn)?shù)四則混合運(yùn)算,注意運(yùn)算順序,注意乘法運(yùn)算定律、減法的性質(zhì)的應(yīng)用.