The highest grade is 9, while 1 is the lowest, and U means "ungraded". The number scale is not directly equivalent to the old letter one. However, the two scales do meet in certain places ...

Leave the ‘Grade type’ as ‘Value’. Select ‘Show more…’ Select ‘Letter’ from the ‘Grade display type’ section. Note if you select ‘Letter (Percentage)’, it will show the letter grade and the percentage ...