MITxplore will hold its twice-a-year Math Day for Grades 4-6 at the MIT Media Lab on Sunday, March 13, 10AM-2:30PM.  Space is limited, and registration is first-come/first-served until filled or until March 6.  It’s free (including lunch and a T-shirt), and donations are appreciated.  For more information, email mitxplore-event@mit.edu.