KenKen Classroom Puzzles That Make Math Fun
Find this brain teaser, All About Adding, (and its answer) in this week's puzzle set: http://www.kenken.com/misc/kkcr/sgnhrwynbzcxxmmbunmahqmhllbafllqyfypgogzdqlyirdcik
Any educator can join for free. Puzzle sets are sent every Friday. A set consists of a variety of levels and sizes that are appropriate for all ages/grade levels.