Sum Fun - A fun number puzzle game for iPhone and iPad.
Lumosity - Discover what your mind can do. Improve memory, increase focus, and find calm - with the #1 brain training app. Get started now.
NumberDrop - A uniquely challenging math puzzle game.
Elevate - Elevate is an award-winning brain training tool designed to build communication and analytical skills.
dworksheets.com - Free K-12 math worksheets to assist students, teachers, parents & tutors to practice, teach or prepare grade school assignments, classwork or homework questions & answers is available online in printable & downloadable format.
Brain Workshop - Brain Workshop is a open-source version of the dual n-back brain training exercise.