Starting this fall, high-school teachers in Orange County will be more forgiving when they grade struggling students.

That's because their principals have agreed to round up student grades to a 50 at the end of the marking period, effectively wiping out any earlier zeros. The plan echoes a similar, long-standing practice at the middle-school level.

However, state law appears to forbid school districts from offering students that cushion.

State statute enshrines 0-59 as the official range for an F in public middle and high schools, and zero percent as the value for an "I" grade (incomplete). A 2009 memorandum to superintendents from the public-schools chancellor said those definitions are non-negotiable.

"It seems to go in the face of the statute," said Diana Moore, president of the Orange County Classroom Teachers Association.