Adult Basic Education:

BBC Skillswise
English and Math for Adults
http://www.bbc.co.uk/skillswise/0/

TV 411
Reading, Writing, Vocabulary, Math, Science, and Finance. Also available in Spanish.
http://www.tv411.org

Khan Academy
https://www.khanacademy.org/

ProLiteracy
Reading, Writing, Math, Vocabulary, and Everyday Skills practice https://proliteracy.org/Professional-Development/Education-Network/Student