I want to award point for certain daily activities

Say 1 point for having done a great job
say 0 points for having done a regular job
say -1 (minus 1) point for a bad job

IN a table I would use "G" for great, "R: for regular, and "B" for bad,
these would be inserted on a daily basis. Basically I want a running tally at
the end of the collum to see where each team member is at in terms of points.

Thank You