Spend an afternoon reviewing statistics. Discover how the Krebs cycle works. Learn about the fundamentals of musical notation. Gain an advantage over the geometry fundamentals of the next semester. Prepare for the SAT, GMAT, LSAT, MCAT or NCLEX-RN. Or, if you feel particularly adventurous, learn how firewood farming changes the landscape of Australia. Whether you are a student, a teacher, a home educator, a director, an adult who returns to the classroom after 20 years or a friendly foreigner who tries to gain an advantage in earthly biology: the Khan Academy's learning library is available to you for free.
(4.4 and up)
KitKat (4.4 - 4.4.4),Lollipop (5.0 - 5.1.1),Marshmallow (6.0 - 6.0.1),Nougat (7.0 – 7.1.1),Oreo (8.0-8.1), Pie(9.0)