考點(diǎn):整數(shù)、分?jǐn)?shù)、小數(shù)、百分?jǐn)?shù)四則混合運(yùn)算,方程的解和解方程,解比例
專題:運(yùn)算順序及法則,簡(jiǎn)易方程
分析:(1)根據(jù)乘法分配律和減法的性質(zhì)進(jìn)行簡(jiǎn)算;
(2)先算加法,再算乘法,最后算除法;
(3)先算加法,再算除法;
(4)、(5)根據(jù)等式的性質(zhì)和比例的基本性質(zhì)進(jìn)行解答;
(6)先算小括號(hào)里面的除法,再算加法,最后算括號(hào)外面的除法;
(7)先算除法,再算加法,最后算乘法;
(8)根據(jù)乘法分配律進(jìn)行簡(jiǎn)算.
解答:
解:(1)(
-
)×7-
=
×7-
×7-
=3-
-
=3-(
+
)
=3-1
=2;
(2)
÷[
×(
+
)]
=
÷[
×
]
=
÷
=
;
(3)
÷(
+
)
=
÷
=
;
(4)600:x=
600÷x=
600÷x×x=
×x
x=600
x÷
=600÷
x=2300;
(5)x:
=
:
x=
×
x=
x÷
=
÷
x=
;
(6)
÷(
+
÷3)
=
÷(
+
)
=
÷1
=
;
(7)(1.75+8.25÷0.6)×1.6
=(1.75+13.75)×1.6
=15.5×1.6
=24.8;
(8)45×
-
÷
=45×
-
×45
=45×(
-
)
=45×1
=45.
點(diǎn)評(píng):考查了運(yùn)算定律與簡(jiǎn)便運(yùn)算,四則混合運(yùn)算.注意運(yùn)算順序和運(yùn)算法則,靈活運(yùn)用所學(xué)的運(yùn)算定律簡(jiǎn)便計(jì)算;
考查了解比例和解方程,根據(jù)比例的基本性質(zhì)和等式的性質(zhì)進(jìn)行解答即可.