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标题: [求助]涛涛GWD-15-22 [打印本页]

作者: louisalz 时间: 2006-6-19 21:05
标题: [求助]涛涛GWD-15-22

Q22:

How many 4-digit positive integers are there in which all 4 digits are even?

A. 625

B. 600

C. 500

D. 400

E. 256

看似很简单的一道题，可是我算出的数巨大，一定犯了什么低级错误，请大侠帮列各式子，谢谢了。

作者: tikyluo 时间: 2006-6-19 21:38

选C么？4*5*5*5=500

4就是[2 4 6 8]

5就是[0 2 4 6 8]

作者: louisalz 时间: 2006-6-19 21:45

谢谢mm，偶的错误果然很低级。。。脑子进水了

式子应该是C（1，4）*C（1，5）*C（1，5）*C（1，5），偶算的时候C（4，9）*C（5，10）*C（5，10）*C（5，10）。。。结果数巨大，彻底晕倒。。。

作者: aliceluca 时间: 2007-7-2 22:46

可是0不是偶数阿。。。。

所以我选的是E 256，4的四次方

作者: melon2004 时间: 2007-8-29 09:23

严重赞同aliceluca!!

零不是偶数.

作者: shamoguzhou 时间: 2007-8-29 09:39
有没有人可以给翻译一下题目阿？晕死了。谢谢

作者: guozili 时间: 2007-10-17 22:55

刚才baidu了一下，似乎现在所有的小学教材都改成0是偶数了，记得小时候老师教的0既不是奇数也不是偶数啊？

那年改的，真行，就决定了这题的对错。

作者: aliciafull 时间: 2008-9-23 16:12
可是我看PREP的数学MATH REVIEW上还说0既不是奇数也不是偶数呀。。。希望不要考到

作者: evilseed 时间: 2008-9-23 16:19

4-digit positive integers

4位数的正整数 ?

麻烦帮忙翻译下..

作者: jz1986111 时间: 2009-5-22 12:13

这个题目是什么意思啊？谢谢

作者: jingle0915 时间: 2010-7-30 16:37
xiexie

作者: caoqin1981 时间: 2011-10-7 10:10
all 4 digits are even我理解成了只要这个四位数本身是偶数，其实是指四位数每位数字都是偶数，我觉得这道题目表述的不严密啊

作者: wildmantomba 时间: 2012-3-10 13:50
从答案上看来 0是偶数
这有点奇怪啊

作者: wildmantomba 时间: 2012-3-10 13:58
according to WIKIPEDIA, ZERO is EVEN

Zero is an even number. In other words, its parity—the quality of an integer being even or odd—is even. Zero fits the definition of "even number": it is an integer multiple of 2, namely 0 × 2. As a result, zero shares all the properties that characterize even numbers: 0 is evenly divisible by 2, 0 is surrounded on both sides by odd numbers, 0 is the sum of an integer (0) with itself, and a set of 0 objects can be split into two equal sets.

Since definitions can change, another approach is to set them aside and consider how zero fits into the patterns formed by other even numbers. The parity rules of arithmetic, such as even ? even = even, require 0 to be even. Zero is the identity element of the group of even integers, and it is the starting case from which other even natural numbers are recursively generated. Applications of this recursion from graph theory to computational geometry rely on zero being even. Not only is 0 divisible by 2, it is divisible by every integer. In the binary numeral system used by computers, it is especially relevant that 0 is divisible by every power of 2; in this sense, 0 is the "most even" number of all.

Among the general public, the parity of zero can be a source of confusion. In reaction time experiments, most people are slower to label 0 as even than 2, 4, 6, or 8. In schools, both students and teachers often hold misconceptions that zero is odd, or both even and odd, or neither. Researchers in mathematics education propose that these misconceptions can become learning opportunities. Studying equalities like 0 × 2 = 0 can address students' doubts about calling 0 a number and using it in arithmetic. Discussing the issue in class can spark debates between students, during which they encounter basic principles of mathematical reasoning, such as the importance of definitions. Understanding zero is one goal, but there is also a wider lesson. Evaluating the parity of this exceptional number is an early example of a pervasive theme in mathematics: the abstraction of a familiar concept to an unfamiliar setting.

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