Y7一道数学题，谁来解一下？

mathsteacher

题目是：
The year 2011 has a repeated digit.  It is in a sequence of consecutive years with  repeated digits.  How long is this sequence?

jackclaire

25  
1988~2012

mathsteacher

jackclaire 发表于 2014-5-22 08:48
25  
1988~2012

谢谢

为什么不是2010~2012？

maths_nz

mathsteacher 发表于 2014-5-22 14:27
谢谢

为什么不是2010~2012？

这肯定是出题老师的不严密，本意应该就是楼上朋友答案那样的问题。

jackclaire

mathsteacher 发表于 2014-5-22 14:27
谢谢

为什么不是2010~2012？

我觉得 1988~2009 这几个年数字也符合题目意思。 有重复数字的，如88，99, 00，而且 1988~2009也连续的。

mathsteacher

噢，我明白了，应该是1988~2012，因为从1988到2012年，每个年份里都有重复的数字出现。答案是25年

Zealandhua

我猜应该是说: 00,11,22,33,44,55,66,77,88,99 共10个.

maths_nz

Zealandhua 发表于 2014-6-12 10:26
我猜应该是说: 00,11,22,33,44,55,66,77,88,99 共10个.

原题应该是问满足那个条件的最长的sequence的长度，当然是从1988-2012了。

Zealandhua

a sequence of consecutive years with  repeated digits,这里有两个条件, 一, 必是顺序的数, 二, 要重复的数
1988-2012不是每个有重复位, 显然不对.
应该是, 2000, 2011, 2022, 2033, 2044, 2055,2066,2077,2088,2099.

maths_nz

Zealandhua 发表于 2014-6-12 15:46
a sequence of consecutive years with  repeated digits,这里有两个条件, 一, 必是顺序的数, 二, 要重复的 ...

Consecutive, 对呀， 2011是其中一个，你写那些没有和2011连着的。

maths_nz

Zealandhua 发表于 2014-6-12 15:46
a sequence of consecutive years with  repeated digits,这里有两个条件, 一, 必是顺序的数, 二, 要重复的 ...

It 指的是2011。

Zealandhua

consecutive 不只是"连续"的意思, 是"顺序一个接一个地". 1,2,3,4,5...是consecutive, 2,4,6,8,...也是consecutive.只要是一个算术序列.

maths_nz

Zealandhua 发表于 2014-6-12 16:03
consecutive 不只是"连续"的意思, 是"顺序一个接一个地". 1,2,3,4,5...是consecutive, 2,4,6,8,...也是cons ...

千万别这么教孩子，呵呵。

maths_nz

Zealandhua 发表于 2014-6-12 16:03
consecutive 不只是"连续"的意思, 是"顺序一个接一个地". 1,2,3,4,5...是consecutive, 2,4,6,8,...也是cons ...

[backcolor=rgba(255, 255, 255, 0)]1，2，3是consecutive numbers, 2,4,6是consecutive even numbers, 2011,2012,2013是consecutive years.

Zealandhua

maths_nz 发表于 2014-6-12 16:07
千万别这么教孩子，呵呵。

你以为是我发明的吗? 我是查了字典才这么说的!
Consecutive integers


Consecutive integers are integers that follow each other in order.We will illustrate with good examples.

Look at the following two sets. The first two are called consecutive positive integer. The last two are called consecutive negative integers

1, 2, 3, 4, 5, 6, 7, ......

12, 14, 16, 18, 20, 22 ......

-1, -2, -3, -4, -5, -6, -7, .....

-30, -32, -34, -36, -38,.....

The first set of consecutive integers is found by adding 1 to 0 and to every positive number that comes after 0

The third set of consecutive integers is found by subtracting 1 from 0 and from every negative number smaller than 0

You can also represent the first set with this expression: n + 1, with n = 0, 1, 2, .....

You can also represent the third set with this expression: 1 − n, with n = 2, 3, 4, 5,.....

If you need to know how to model the second and the fourth with an expression, study this lesson:

Consecutive even integers

A set of integers such that each integer in the set differs from the integer immediately before by a difference of 2 and each integer is divisible by 2

Example

2, 4, 6, 8, 10, 12, 14,....

You can represent this set with the following expression: 2n + 2 with n = 0, 1, 2, 3....

Consecutive odd integers

A set of integers such that each integer in the set differs from the integer immediately before by a difference of 2 and each integer is an odd number

Example

1, 3, 5, 7, 9, 11, 13,....

You can represent this set with the following expression: 2n + 1 with n = 0, 1, 2, 3....

maths_nz

Zealandhua 发表于 2014-6-12 16:12
你以为是我发明的吗? 我是查了字典才这么说的!
Consecutive integers

只是建议，呵呵。
你这里也说了，consecutive integers and consecutive odd integers are different.

Zealandhua

maths_nz 发表于 2014-6-12 16:09
1，2，3是consecutive numbers, 2,4,6是consecutive even numbers, 2011,2012,2013是consecutive years.[ ...

你认为 2000, 2011, 2022, 2033, 2044, 2055, 2066, 2077, 2088, 2099不是consecutive years?

maths_nz

Zealandhua 发表于 2014-6-12 16:17
你认为 2000, 2011, 2022, 2033, 2044, 2055, 2066, 2077, 2088, 2099不是consecutive years?

当然不是。

maths_nz

Zealandhua 发表于 2014-6-12 16:17
你认为 2000, 2011, 2022, 2033, 2044, 2055, 2066, 2077, 2088, 2099不是consecutive years?

你只能说consecutive years with four digits and the first two are 20, the last two are repeat digit.

Zealandhua

maths_nz 发表于 2014-6-12 16:18
当然不是。

这是一个公差为11的完美的整数序列!

maths_nz

maths_nz 发表于 2014-6-12 16:20
你只能说consecutive years with four digits and the first two are 20, the last two are repeat digit ...

呵呵，我说这个也有毛病。

maths_nz

Zealandhua 发表于 2014-6-12 16:21
这是一个公差为11的完美的整数序列!

呵呵，是一个公差为11的整数序列，so?

Zealandhua

maths_nz 发表于 2014-6-12 17:53
呵呵，是一个公差为11的整数序列，so?

是的. 这就是答案, 10个!

Zealandhua

jackclaire 发表于 2014-5-22 08:48
25  
1988~2012

你这个数列中,有几个含"repeat digits" ?

maths_nz

Zealandhua 发表于 2014-6-12 22:25
你这个数列中,有几个含"repeat digits" ?

友情回答，都有。

Zealandhua

maths_nz 发表于 2014-6-12 22:37
友情回答，都有。

你很坚强啊.

maths_nz

Zealandhua 发表于 2014-6-12 22:43
你很坚强啊.

呵呵，闲着也是闲着。老师，您知道什么叫一个数含"repeat digits"?

Zealandhua

maths_nz 发表于 2014-6-12 22:47
呵呵，闲着也是闲着。老师，您知道什么叫一个数含"repeat digits"?

你说说看是何意?

maths_nz

Zealandhua 发表于 2014-6-12 23:03
你说说看是何意?

我觉得吧，2012就含有一个重复的数字2，您好像不太认同。希望您会改变呵呵。

Zealandhua

maths_nz 发表于 2014-6-12 23:08
我觉得吧，2012就含有一个重复的数字2，您好像不太认同。希望您会改变呵呵。

你是对的.