Simplify the following text for a Grade 4 native English-speaking person.
Original: Common equivalent models are the multi-tape Turing machine , multi-track Turing machine , machines with input and output , and the non-deterministic Turing machine ( NDTM ) as opposed to the deterministic Turing machine ( DTM ) for which the action table has at most one entry for each combination of symbol and state .
Simplified: There are two purposes of a Turing machine .