mathematics

A positive whole number is called stable, if at least one of its digits has the same value as its position in the number. Example, 78247 is stable because a 4 appears in the 4th position. How many stable 3-digit numbers are there?

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  2. 👎 0
  3. 👁 415
  1. the number must have the form
    xx3 or x2x or 1xx
    Since there are no leading zeroes, that leaves
    9*10 + 9*10 + 10*10 possibilities

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    2. 👎 2
    👨‍🏫
    oobleck
  2. Answer is 252.

    You should not double count numbers.

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  3. Yeet a yeet

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