nice and renice command syntax clarification

The nice and renice commands have different ways of specifying the amount that is to be added to the standard nice value of 20.

Nice Command Renice Command Resulting nice Value Best Priority Value
nice -n 5 renice -n 5 25 70
nice -n +5 renice -n +5 25 70
nice -n -5 renice -n -5 15 55