Fastest way I could find.
Load up a easy suduko challenge from the challenges menu.
There are 3 of these a day so should be easy to find an easy suduko one.
These are usually complete 3 rows or columns.
Now fill ever square with 1 to 9 of notes.
Now complete the puzzle for the notes to count towards your total.
Potential to do around 450 notes in one game which help towards the Notary Acheivement.
Solution will also unlock :