Does Jesus have a last name? I heard "Christ" isn't the last name He got from His parents. Is that true? Does He have a last name?

If He does not have a last name, then how does that work? If that wasn't His last name, and there were other people named Jesus, then how could people even know which Jesus people were talking about?

Please explain this to me in an easy to understand way, like if I am young.
Surnames didn't exist in Jesus' day. 

People typically referred to somebody by referring to their parentage.  So Jesus would have most likely been referred to as "Jesus son of Joseph" or "Jesus son of Mary", much in the same way as Peter was referred to as "Simon, son of Jonah" in Matthew 16:17 and "James son of Zebedee" in Mark 3:17.

While nobody is entirely sure when the concept of the proper surname began, one guess, at least for English speakers, is around the 13th or 14th century. 

http://en.wikipedia.org/wiki/Family_name#Modern_era