Below are four PDF file Math workbooks. The first three are from PAX Learning Center and the fourth is from Tyler Wallace. Below that are video links. Click on the pictures to go to the websites.
IXL Language Arts. This site contains; main idea, themes, purpose, comparing text and structure.
UShistory.org This site is filled with short reads about U.S. History. Some parts are followed up with quizzes and tests.
IXL Science This site has pretty much everything you'll need to know to pass the GED Science test.
ged.com. the best place to start. The first step is to create an account. This allows you to begin taking practice tests. You can also find short practice tests
onlinepractice.newreaderspress.com has practice tests that look just like the real test. Great place to practice at. Create an account and get started.