分析:(1)通分計(jì)算;
(2)運(yùn)用減法的性質(zhì)簡(jiǎn)算;
(3)先算括號(hào)內(nèi)的,再算括號(hào)外的;
(4)運(yùn)用加法交換律與結(jié)合律簡(jiǎn)算;
(5)把每個(gè)分?jǐn)?shù)拆成兩個(gè)分?jǐn)?shù)相減的形式,然后通過加減相抵消的方法,求出結(jié)果;
(6)把每個(gè)分?jǐn)?shù)拆成“整數(shù)+分?jǐn)?shù)”的形式,整數(shù)與整數(shù)相加,分?jǐn)?shù)與分?jǐn)?shù)相加.
解答:解:(1)
-
+
,
=
-
+
,
=
;
(2)2
-
-
,
=2
-(
+
),
=2
-1,
=1
;
(3)
-(
+
),
=
-
,
=
;
(4)
+
+
+
,
=(
+
)+(
+
),
=1+1,
=2;
(5)
+
+
+
,
=1-
+
-
+
-
+
-
,
=1-
,
=
;
(6)9
+99+999,
=(9+
)+(99+
)+(999+
),
=(9+99+999)+
×3,
=(10-1+100-1+1000-1)+2
,
=1110-3+2
,
=1110-(3-2
),
=1110-
,
=1109
.
點(diǎn)評(píng):完成此題,應(yīng)認(rèn)真分析數(shù)據(jù),注意運(yùn)算順序,以及運(yùn)用運(yùn)算性質(zhì)或運(yùn)算定律進(jìn)行簡(jiǎn)算.