考點(diǎn):整數(shù)、分?jǐn)?shù)、小數(shù)、百分?jǐn)?shù)四則混合運(yùn)算,分?jǐn)?shù)的簡(jiǎn)便計(jì)算
專題:運(yùn)算順序及法則,運(yùn)算定律及簡(jiǎn)算
分析:(1)運(yùn)用乘法交換律解答,
(2)按照先算括號(hào)里面的減法,再算乘法,最后算加法順序計(jì)算解答,
(3)運(yùn)用乘法分配律解答,
(4)按照先算小括號(hào)里面的加法,再算中括號(hào)里面的減法,最后算括號(hào)外面的除法順序解答,
(5)根據(jù)乘法分配律先算中括號(hào)里的,
(6)按照先算小括號(hào)里面的減法,再算中括號(hào)里面的乘法,然后算除法,最后算加法順序計(jì)算解答.
解答:
解:(1)0.8×33×1.25
=0.8×1.25×33
=1×33
=33;
(2)
+
×(
-
)
=
+
×
=
+2
=2
;
(3)
×
+
×
=(
+
)×
=2×
=
;
(4)
÷[
-(
+
)]
=
÷[
-
]
=
÷=1
;
(5)
×3÷[12×(3.75+
)]
=
×3÷[12×3.75+12×
]
=
×3÷77
=
(6)6.4+3.6÷[(
-3.5)×
]
=6.4+3.6÷[
×
]
=6.4+3.6÷6
=6.4+0.6
=7.
點(diǎn)評(píng):(1)依據(jù)四則運(yùn)算計(jì)算方法正確進(jìn)行計(jì)算,(2)運(yùn)用簡(jiǎn)便方法解決問(wèn)題,是本題考查知識(shí)點(diǎn).