Here is the full list of all 12 Are You Smarter Than a 5th Grader? (2008) achievements worth 200 gamerscore.
Collect 1 Extra Credit Star
Collect 30 Extra Credit Stars
Collect 70 Extra Credit Stars
Collect all of the Extra Credit stars
Get 500 answers correct
Get an answer correct in under 3 seconds
Peek at your classmate's paper but don't follow
Win One Million Dollars in any game
Win One Million Dollars without cheating
Win One Million Dollars in under 5 minutes
Come first in a multiplayer game
For me to know and you to find out