题目内容
“步步成功”,我能行.
|
|
5-
| ||||||||||||||||
1-﹙
|
|
|
考点:分数的加法和减法
专题:运算顺序及法则
分析:
(3)把5-
-
改写成减去两个数的和简算;
(6)把
-﹙
+
﹚改写成连续减去两个数简算;
(2)(4)(5)按照运算顺序计算得解.
(1)
|
4 |
11 |
7 |
11 |
(6)把
9 |
14 |
3 |
14 |
1 |
7 |
(2)(4)(5)按照运算顺序计算得解.
解答:
解:(1)
+
+
=
+(
+
)
=1
(2)
+
-
=
+
-
=
(3)5-
-
=5-(
+
)
=5-1
=4
(4)1-﹙
-
﹚
=1-(
-
)
=1-
=
(5)
-
+
=
-
+
=
(6)
-﹙
+
﹚
=
-
-
=
-
=
.
5 |
6 |
3 |
7 |
1 |
6 |
=
3 |
7 |
5 |
6 |
1 |
6 |
=1
3 |
7 |
(2)
1 |
2 |
3 |
4 |
3 |
10 |
=
10 |
20 |
15 |
20 |
6 |
20 |
=
19 |
20 |
(3)5-
4 |
11 |
7 |
11 |
=5-(
4 |
11 |
7 |
11 |
=5-1
=4
(4)1-﹙
3 |
4 |
1 |
6 |
=1-(
9 |
12 |
2 |
12 |
=1-
7 |
12 |
=
5 |
12 |
(5)
4 |
5 |
3 |
10 |
2 |
3 |
=
24 |
30 |
9 |
30 |
20 |
30 |
=
7 |
6 |
(6)
9 |
14 |
3 |
14 |
1 |
7 |
=
9 |
14 |
3 |
14 |
1 |
7 |
=
6 |
14 |
2 |
14 |
=
2 |
7 |
点评:此题考查分数加减法的混合运算,能运用运算定律简算的就简算,不能简算的就按照运算顺序计算,要注意计算过程中先通分成同分母分数再计算,结果要化成最简分数.
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