考點(diǎn):分?jǐn)?shù)的四則混合運(yùn)算
專題:運(yùn)算順序及法則
分析:①先計(jì)算乘除,最后計(jì)算減法,注意分?jǐn)?shù)的約分化簡(jiǎn).
②運(yùn)用一個(gè)數(shù)連續(xù)減去兩個(gè)數(shù),可以用這個(gè)數(shù)減去這兩個(gè)數(shù)的和.
③先計(jì)算乘除,最后計(jì)算加法,注意分?jǐn)?shù)的約分化簡(jiǎn).
④先計(jì)算中括號(hào)內(nèi)部的,再計(jì)算中括號(hào)外面的,注意分?jǐn)?shù)的約分化簡(jiǎn).
⑤先計(jì)算除法,然后再計(jì)算減法.
⑥先計(jì)算除法,然后再運(yùn)用乘法的分配律進(jìn)行計(jì)算即可.
解答:
解:①
×
-
÷
=1-
=
②4-
-
=4-(
+)
=4-
=
③
×
+
÷
=
+
=
④
÷[(
-
)÷
]
=
÷[
×
]
=
÷
=
×5
=4
⑤1-
÷
-
=1-
×-=1-
-=0
⑥
÷
+
×
=
×
+×
=
×(
+)
=
點(diǎn)評(píng):本題考查了學(xué)生通過(guò)約分對(duì)分?jǐn)?shù)四則混合運(yùn)題目進(jìn)行簡(jiǎn)算的能力.