题目内容
观察下列各式的计算结果
1-
=1-
=
=
×
1-
=1-
=
=
×
1-
=1-
=
=
×
1-
=1-
=
=
×
(1)用你发现的规律填写下列式子的结果
1-
= ,1-
=
(2)用你发现的规律计算
(1-
)×(1-
)×(1-
)••…(1-
).
1-
| 1 |
| 22 |
| 1 |
| 4 |
| 3 |
| 4 |
| 1 |
| 2 |
| 3 |
| 2 |
1-
| 1 |
| 32 |
| 1 |
| 9 |
| 8 |
| 9 |
| 2 |
| 3 |
| 4 |
| 3 |
1-
| 1 |
| 42 |
| 1 |
| 16 |
| 15 |
| 16 |
| 3 |
| 4 |
| 5 |
| 4 |
1-
| 1 |
| 52 |
| 1 |
| 25 |
| 24 |
| 25 |
| 4 |
| 5 |
| 6 |
| 5 |
(1)用你发现的规律填写下列式子的结果
1-
| 1 |
| 102 |
| 1 |
| 1002 |
(2)用你发现的规律计算
(1-
| 1 |
| 22 |
| 1 |
| 32 |
| 1 |
| 42 |
| 1 |
| 20122 |
考点:规律型:数字的变化类
专题:
分析:(1)根据平方差公式即可求解;
(2)先根据平方差公式变形,再约分计算即可求解.
(2)先根据平方差公式变形,再约分计算即可求解.
解答:解:(1)1-
=
×
;
1-
=
×
;
(2)原式=
×
×
×
×
×
×…×
×
=
×
=
.
| 1 |
| 102 |
| 9 |
| 10 |
| 11 |
| 10 |
1-
| 1 |
| 1002 |
| 99 |
| 100 |
| 101 |
| 100 |
(2)原式=
| 1 |
| 2 |
| 3 |
| 2 |
| 2 |
| 3 |
| 4 |
| 3 |
| 3 |
| 4 |
| 5 |
| 4 |
| 2011 |
| 2012 |
| 2013 |
| 2012 |
=
| 1 |
| 2 |
| 2013 |
| 2012 |
=
| 2013 |
| 4024 |
点评:此题考查了数字的变化规律,熟练掌握平方差公式是解本题的关键.
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