Judy Woodruff:

More than half-a-million students and their parents were dealing with the first day of a huge teachers strike in the Los Angeles Unified School District, a district that is 700 square miles and stretches well beyond the city limits.

It's the first strike there in three decades.

And as special correspondent Mary MacCarthy tells us, there are some big dividing lines between the union and the district.

It's the focus tonight of our weekly education segment, Making the Grade.