Unique Integer Count
Number Theory
Level
3
One can dial maximum 99 digits number(without using any operators) in a CASIO fx - 991ES PLUS calculator . How many unique positive integer number(excluding 0) could be dialed in that calculator?
- 1
None of above
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1 solution
Every digit from 1st to 99th can contain 0,1,2,3,4,5,6,7,8,9 number. So the 1st digit could be filled in 10 ways. This goes same for the next and next and so on to the 99th digit. So putting it this way we get 10x10x10...... = 1 0 9 9 . But there is a number where every digit is filled with 0. So we have to exclude that. Thus the answer is || 1 0 9 9 -1||