题目内容
能简算的要简算.









.
解:(1)
,
=
+
+
,
=1+
,
=1
;
(2)
,
=
-
-
,
=
-
,
=
;
(3)
,
=2-(
+
),
=2-1,
=1;
(4)
,
=
-
,
=
;
(5)
,
=(
+
)+(
+
),
=1+1,
=2;
(6)
,
=1
-(
+
),
=1
-1,
=
;
(7)
,
=3-
,
=2
;
(8)
,
=
-
,
=
;
(9)
,
=
-
+
,
=
+
,
=
;
(10)
,
=(
+
)+(
-
),
=1+
,
=1
.
分析:(1)运用加法交换律简算;
(2)(3)(6)根据减法的性质简算;
(4)(8)按照从左到右的顺序计算;
(5)(10)运用加法交换律和结合律简算;
(7)先算小括号里面的减法,再算括号外的减法;
(9)先去括号,再按照从左到右的顺序计算.
点评:本题考查了基本的分数的加减混合运算,要注意分析数据,选择合适的简算方法简算.
=
=1+
=1
(2)
=
=
=
(3)
=2-(
=2-1,
=1;
(4)
=
=
(5)
=(
=1+1,
=2;
(6)
=1
=1
=
(7)
=3-
=2
(8)
=
=
(9)
=
=
=
(10)
=(
=1+
=1
分析:(1)运用加法交换律简算;
(2)(3)(6)根据减法的性质简算;
(4)(8)按照从左到右的顺序计算;
(5)(10)运用加法交换律和结合律简算;
(7)先算小括号里面的减法,再算括号外的减法;
(9)先去括号,再按照从左到右的顺序计算.
点评:本题考查了基本的分数的加减混合运算,要注意分析数据,选择合适的简算方法简算.
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