SOLUTION: How many three-digit counting numbers less than 500 have digits that are all odd?

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Question 1080905: How many three-digit counting numbers less than 500 have digits that are all odd?
Found 2 solutions by Boreal, ikleyn:
Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
Have to look at numbers between 100 and 199 and 300-399. Find one, and the other will be the same.
111,113,115,117,119
131
151
171
191
25 of them here
25 between 300 and 399
50
Answer by ikleyn(52824)   (Show Source): You can put this solution on YOUR website!
.
In the 1-st (leftmost) position the digits are 1 or 3 (2 options).

In the next, 2-nd position, the digits are 1, or 3, or 5, or 7, or 9 (5 options).

In the last, 3-rd position, the digits are 1, or 3, or 5, or 7, or 9 (5 options).


In all, there are 2*5*5 = 50 such numbers.


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