考點(diǎn):分?jǐn)?shù)的四則混合運(yùn)算,分?jǐn)?shù)的簡(jiǎn)便計(jì)算
專(zhuān)題:運(yùn)算順序及法則,運(yùn)算定律及簡(jiǎn)算
分析:(1)先把除法變成乘法,再運(yùn)用乘法分配律簡(jiǎn)算;
(2)運(yùn)用乘法分配律簡(jiǎn)算;
(3)先算除法,再運(yùn)用減法的性質(zhì)簡(jiǎn)算;
(4)先算小括號(hào)里面的加法,再算括號(hào)外的除法,最后算減法;
(5)先算小括號(hào)里面的減法,再算乘法,最后算除法;
(6)按照從左到右的順序計(jì)算.
解答:
解:(1)
÷7+
×
=
×
+
×
=(
+
)×
=
×
=
;
(2)(
+
-
)×12
=
×12+
×12-
×12
=9+8-2
=15;
(3)2-
÷
-
=2-
-
=2-(
+
)
=2-2
=0;
(4)1-(
+
)÷
=1-
÷
=1-
=-
;
(5)
×
÷(
-
)
=
×
÷
=
×
=
;
(6)
×0.375÷
=
×
÷
=
×
=
.
點(diǎn)評(píng):本題考查了四則混合運(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)算定律進(jìn)行簡(jiǎn)便計(jì)算.