How many three digit numbers consist only of odd digits?

I need to know how to figure out this question as well as the answer.How many three digit numbers consist only of odd digits?
If you don't count zero, they follow a pattern:


111,113,115,117,119


then 131,133 etc.


So there are five numbers for each group of ten, then five groups per hundred. There are five hundreds in the total set of 3 digit numbers, so 5 x 5 x 5=125.How many three digit numbers consist only of odd digits?
if you count 001 as 1 then there are 999 possible total combonations...if you cant then 100 being the first counted


you would have 99 less.. .or 900 total combonations.


removing all the even hundreds..thats 400 .. leaving 500


removing all the even tens ..40 x 5 is 200.. leaving 300


if you count all less then tens.. 101 102 ,301 302 ect ect..


there is 9 in each group of odd hundreds..9 x 5. leaving 255


and the other zeros thats left is 5 x 5 leaving 230


out of the 230 left.. half end with even numbers 115


so my guess is 115 combonations of odd digits





there is another way to fiqure this out. but its been so long since i use based numbers.. forgot how to convert them..





using only 1 3 5 7 9 would be base 5..





you could go down the list and count them..





111


113


115


117


119


131


133


135


137


139


151


153


155


157


159


171


173


175


177


179


191


193


195


197


199





this way i count 25 for each hundred...


so 25 x 5 is 125 combonations... 10 off using the other method
50 numbers 2x5x5