题目内容
脱式计算.
+
+
1-
-
1-(
+
)
-
+
.
1 |
6 |
1 |
3 |
1 |
4 |
1-
1 |
2 |
1 |
3 |
1-(
3 |
8 |
1 |
6 |
5 |
6 |
2 |
7 |
1 |
6 |
分析:本题根据异分母分数加法与减法的运算法则计算即可:异分母分数相加减,要先经过通分将异分母分数变为同分母分数后,再按同分母分数相加减的计算法则进行计算.算式(4)可据加法交律进行计算.
解答:解:(1)
+
+
,
=
+
+
,
=
,
=
;
(2)1-
-
,
=1-
-
,
=
;
(3)1-(
+
),
=1-(
+
),
=1-
,
=
;
(4)
-
+
,
=
+
-
,
=1-
,
=
.
1 |
6 |
1 |
3 |
1 |
4 |
=
2 |
12 |
4 |
12 |
3 |
12 |
=
9 |
12 |
=
3 |
4 |
(2)1-
1 |
2 |
1 |
3 |
=1-
3 |
6 |
2 |
6 |
=
1 |
6 |
(3)1-(
3 |
8 |
1 |
6 |
=1-(
9 |
24 |
4 |
24 |
=1-
13 |
24 |
=
11 |
24 |
(4)
5 |
6 |
2 |
7 |
1 |
6 |
=
5 |
6 |
1 |
6 |
2 |
7 |
=1-
2 |
7 |
=
5 |
7 |
点评:完成此类题目的关键是要细心,注意通分约分.
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