1. **State the problem:** Alex has signed 122 comic books out of 327 total. We want to find how many comic books, $c$, he still needs to sign. 2. **Write the equation:** The problem gives the equation: $$122 + c = 327$$ This means the number signed plus the number left equals the total. 3. **Isolate $c$:** To find $c$, subtract 122 from both sides: $$122 + c - \cancel{122} = 327 - \cancel{122}$$ which simplifies to: $$c = 327 - 122$$ 4. **Calculate the difference:** $$c = 205$$ 5. **Interpret the result:** Alex still needs to sign 205 comic books. **Final answer:** $$\boxed{205}$$