题目内容
括号里填上适当的数,使等式成立
=
+
;
=
+
;
=
+
;
=
+
.
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| 1 |
| ( ) |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| ( ) |
| 1 |
| 4 |
| 1 |
| ( ) |
| 1 |
| ( ) |
| 1 |
| 5 |
| 1 |
| ( ) |
| 1 |
| ( ) |
分析:先计算前两题:用两数的和减去已知的加数可得:
=
+
;
=
+
;发现
可以分解成:
+
(n是不为0的自然数),再由此规律求解.
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| 3 |
| 1 |
| 6 |
| 1 |
| 3 |
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| 4 |
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| 12 |
| 1 |
| n |
| 1 |
| n+1 |
| 1 |
| n(n+1) |
解答:解:
=
+
;
=
+
;
=
+
;
=
+
.
故答案为:6;12;5,20;6,30.
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 6 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 12 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 20 |
| 1 |
| 5 |
| 1 |
| 6 |
| 1 |
| 30 |
故答案为:6;12;5,20;6,30.
点评:先计算出部分算式,找出规律,再根据规律求解.
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