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Problem 17

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Number letter counts

If the numbers $1$ to $5$ are written out in words: one, two, three, four, five, then there are $3 + 3 + 5 + 4 + 4 = 19$ letters used in total.

If all the numbers from $1$ to $1000$ (one thousand) inclusive were written out in words, how many letters would be used?

NOTE: Do not count spaces or hyphens. For example, $342$ (three hundred and forty-two) contains $23$ letters and $115$ (one hundred and fifteen) contains $20$ letters. The use of “and” when writing out numbers is in compliance with British usage.

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整数英文表达的字母计数

把$1$到$5$写成英文单词分别是：one、two、three、four、five。这些单词一共用了$3 + 3 + 5 + 4 + 4 = 19$个字母。

如果把$1$到$1000$都写成英文单词，一共要用多少个字母？

注意： 不计入空格和连字符：例如，$342$（three hundred and forty-two）包含$23$个字母，而$115$（one hundred and fifteen）包含$20$个字母。单词“and”的使用方式遵循英式英语的规则。

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