How often does 7 occur from number 1 to 1000?

8,719

Consider the number of times $7$ appears (a) as the units digit, (b) as the tens digit, (c) as the hundreds digit and add them together.

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8,719

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user301837
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Updated on January 02, 2020

Comments

  • user301837
    user301837 almost 4 years

    How many times will the digit $7$ be written when listing the integers from $1$ to $1000$?

    Is the following method correct?

    For a single $7$,

    $($C(1,1)$ \times$C(9,1)$\times$C(9,1)$)$$\times$3!

    etc...

    • Empy2
      Empy2 almost 8 years
      Answer it from 1 to 10; from 1 to 100.
    • Empy2
      Empy2 almost 8 years
      Write numbers down to see how many 7s you will get