题目内容
计算
+
+
-
-
+
.
5 |
12 |
3 |
4 |
1 |
12 |
7 |
10 |
3 |
8 |
1 |
8 |
4 |
15 |
5 |
6 |
考点:分数的加法和减法
专题:运算顺序及法则
分析:(1)根据加法交换律进行简算;
(2)根据减法的性质进行简算;
(3)先通分,再计算.
(2)根据减法的性质进行简算;
(3)先通分,再计算.
解答:
解:(1)
+
+
=
+
+
=
+
=
;
(2)
-
-
=
-(
+
)
=
-
=
;
(3)
+
=
+
=
=
.
5 |
12 |
3 |
4 |
1 |
12 |
=
5 |
12 |
1 |
12 |
3 |
4 |
=
1 |
2 |
3 |
4 |
=
5 |
4 |
(2)
7 |
10 |
3 |
8 |
1 |
8 |
=
7 |
10 |
3 |
8 |
1 |
8 |
=
7 |
10 |
1 |
2 |
=
1 |
5 |
(3)
4 |
15 |
5 |
6 |
=
8 |
30 |
25 |
30 |
=
33 |
30 |
=
11 |
10 |
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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