考點(diǎn):分?jǐn)?shù)的四則混合運(yùn)算,運(yùn)算定律與簡(jiǎn)便運(yùn)算
專題:運(yùn)算順序及法則,運(yùn)算定律及簡(jiǎn)算
分析:(1)先算減法,再算乘法;
(2)(3)(4)(5)(6)(7)(8)(10)(11)利用乘法分配律簡(jiǎn)算;
(9)直接約分計(jì)算即可;
(12)利用乘法交換律與結(jié)合律簡(jiǎn)算.
解答:
解:(1)
×(
-
)
=
×
=
;
(2)(13+
)×
=13×
+
×
=9+
=9
;
(3)
×12+
=
×(12+1)
=
×13
=66;
(4)(
+
)×32
=
×32+
×32
=24+20
=44;
(5)(
+
)×32
=
×32+
×32
=24+20
=44;
(6)
×11-
=
×(11-1)
=
×10
=9;
(7)
×
+
×
=
×(
+
)
=
×1
=
;
(8)36×(
+
-
)
=36×
+36×
-36×
=27+8-30
=5;
(9)
×
×
=
;
(10)101×
-
=(101-1)×
=100×
=20;
(11)
×48
=
×47+
×1
=6+
=6
;
(12)
×34×7×
=
×7×(
×34)
=1×4
=4.
點(diǎn)評(píng):分?jǐn)?shù)混合運(yùn)算的關(guān)鍵是抓住運(yùn)算順序,正確按運(yùn)算順序計(jì)算,適當(dāng)利用運(yùn)算定律簡(jiǎn)算.