5th grade is our problem too. ds just finished 4th. He was subject accelerated 2 years in math and in reading since 1st grade. The school only goes to 5th so this year in 4th was lacking a bit. We supplement with a tutor from the high school and went through the AoPS pre algebra book. We also did some Saturday classes at the local universities (more for fun) and got his feet wet with some math competitions.

The school says basically they have nothing to offer outside the scope of their high ability cluster group. There enrichment this year was an extra math sheet once a week for math. He did go through both Caesar's English books. He blew through the regular stuff with a grimace on his face. He usually got the extra done in class too.

Maps testing charts growth over the year and from year to year.

5th grade we have opted for a private school for gifted.
It seems to be the perfect option. Price excluded.