Conclusions:
I. Some Signs are Symbols.
II. Some Signs are not Marks.
III. No Number is a Mark. Statements:

From Statement I. No Sign is a Number (E) + All Numbers are Symbols (A) → Some Symbols are not Signs (O*). Hence neither conclusion I nor II follow. All Numbers are Symbols (A) + Some Symbols are Marks (I) → No conclusion. Hence conclusion III does not follow.   From Statement II. Only a few Signs are Numbers (I) + All Numbers are Symbols (A) → Some Signs are Symbols (I). Hence conclusion I follows. Only a few Signs are Numbers (I) + All Numbers are Symbols (A) → Some Signs are Symbols (I) + No Symbol is a Mark (E) → Some Signs are not Marks (O). Hence conclusion II follows. All Numbers are Symbols (A) + No Symbol is a Mark (E) → No Number is a Mark (E). Hence conclusion III follows.   From Statement III. No Symbol is a Sign (E) → Conversion → No Sign is a Symbol (E). Hence conclusion I does not follow. Some Marks are Numbers (I) + Some Numbers are Symbols (I) → No conclusion. Hence neither conclusion II nor III follow.   From Statement IV. All Signs are Symbols (A) → I.I. → Some Signs are Symbols (I). Hence conclusion I follows. All Signs are Symbols (A) +   All Symbols are Numbers (A) → All Signs are Numbers (A) + Only a few Numbers are Marks (I) → No conclusion. Hence conclusion II does not follow. Only a few Numbers are Marks → Some Numbers are Marks (I). Hence conclusion III does not follow.