I AM AN ODD NUMBER WITH FOUR DIGITS. MY TENS AND HUNDREDS DIGITS ARE EVEN. THE SUM OF MY DIGITS IS 16
Ans:
With the given information, there is no unique solution to the problem. All we
can conclude is:
1) 10's and 100's digits are even. 
2) since the number is odd, unit's digit is odd. 
3) since the sum is 16 which is an even number, the 1000's digit has to be odd.
There are many numbers which satisfy the above conditions.
e.g. 3265 plus some of its permutations like 3625, 5263, 5623
1267, 1627, 7621, 7261
It is not clear whether all 4 digits are different. If we allow repeated digits,
then we also have solutions like:
3445, 5443 etc.
Are you asking for one solution (there is no unique answer) or the number of 
possible solutions?
:)