解:①
×
+
4,
=
×
+
,
=(
)×
,
=1×
,
=
;
②3.8×999+3.8,
=(999+1)×3.8,
=1000×3.8,
=3800;
③(
+
-
)÷
,
=(
+
-
)×48,
=
×48+
48-
×48,
=24+6-8,
=22;
④444-47+546-53,
=(444+546)-(47+53),
=990-100,
=890;
⑤5000-27÷18×106,
=5000-
106,
=5000-159,
=4841;
⑥
+
+…+
+
,
=(
)+(
)+…+(
)+(
),
=
-
,
=
,
=
.
分析:①先把除法改為乘法,然后運(yùn)用乘法分配律的逆運(yùn)算簡(jiǎn)算;
②把3.8看作3.8×1,運(yùn)用乘法分配律的逆運(yùn)算簡(jiǎn)算;
③先把除法改為乘法,根據(jù)數(shù)字特點(diǎn),運(yùn)用乘法分配律簡(jiǎn)算;
④運(yùn)用加法交換律和結(jié)合律以及減法的性質(zhì),進(jìn)行簡(jiǎn)算;
⑤為了便于計(jì)算,把27÷18寫(xiě)成分?jǐn)?shù)形式,能夠約分,使計(jì)算簡(jiǎn)單化;
⑥先把每個(gè)分?jǐn)?shù)變?yōu)榉謹(jǐn)?shù)相減的形式,然后通過(guò)加、減相抵消的方法,簡(jiǎn)算出結(jié)果.
點(diǎn)評(píng):在解答計(jì)算題時(shí),首先應(yīng)仔細(xì)審題,巧妙靈活地運(yùn)用運(yùn)算定律,使復(fù)雜的計(jì)算簡(jiǎn)單化.