range of function

Question

The function that assigns to each positive integer the number of the digits 0,1,2,3,4,5,6,7,8,9 that do not appear as digits in the decimal representation of the integer.

what is range ?

solution says it is not one one and onto so no range but i am not getting meaning of that question

Comments

can u give an example what is language of question i m not getting it?

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take a positive integer, say, 47820. then out of {0,1,2,3,4,5,6,7,8,9}, how many of these digits are not appearing in 47820. answer would be 5. as 1,3,5,6,9 are not there in 47820. do this for all the positive integers. crux here is can we get > 9 and less then 0. answer is no. hence range is as already given.

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oh yes thank u so much