This is a riddle my friend gave me and we don't know the answer so we would like some help. The task is to use all of the numbers $0,1,2,...,9$ once each to get a sum of $100$ only using the plus sign.
You can do whatever you want with the numbers so long the plus sign and only that is included. For example, one could concatenate and use the number $12$ or $23$.
Multiplications or exponents or other signs are not allowed.