1. Correct
2. Correct
3. Correct
4. Wrong, but correct answer was already guessed by BlueCube
5. Correct
6. Wrong, like I so ineliquently tried to describe before, you can only have two numbers written down, not two digits written a million times. Because even your answer, 900000000000000000.... isn't theoretically larger than 990000000000000000.... for example.