Need help adding zero each time the sum of two characters within a string is less than 10

Hi all.
I am a new registrant and have the following question.

I have a series of number strings such as:
1 – 2 – 18 – 25 – 45 – 5 – 8 – 17 – 99 – and so on.

Each number string is in a different cell (such as A1, A2, A3 and so on).

I want to add a number zero at each instance where a character in a string is less than ten so that all numbers within each string will have two characters, for example:
01 – 02 – 18 – 25 – 45 – 05 – 08 – 17 – 99

Each string is a different cell. The largest two character number within each string is 99. I am using Excel 2010 and Explorer 10. Any suggestions?

I will appreciate your responses.

Thank you.

Fred