You can learn anything, offline.

Mathematics

Algebra-Algebra2Go

Early Math-Khan Academy

Geometry-Khan Academy

Calculus-Khan Academy

English

Learn English-African Storybook Project

Children Storybooks-Book Dash

African Languages

Learn Swahili-African Storybook Project

Learn Maasai-African Storybook Project

Physics

Learn Physics-Khan Academy

Biology

Learn Biology-Khan Academy

Chemistry

Learn Chemistry-Khan Academy

Free E-books

Read and download e-books-Project Gutenberg