There are collusions, meaning multiple words result in the same hash. If you find a collusion, then yes, the system will most likely accept the password/string.
Although, md5 does a bit more than what described above. The md5 of the string "the" is 8fc42c6ddf9966db3b09e84365034357, and not 8 or 800.
I suggest you to read this:
Hashing Myths - webdevRefinery Forum
It's a very interesting read.