A collection of around 150 videos aligned to our Prealgebra textbook. A growing collection of over 70 videos aligned to our Introduction to Algebra textbook. A collection of over 80 videos aligned to our Introduction to Counting & Probability textbook. These videos are also integrated with our Alcumus online learning system. MATHCOUNTS Minis, videos we produce for use on the MATHCOUNTS site. MATHCOUNTS is the premier middle school competition (ages 11-14) in the United States. AMC videos covering the hardest problems on the AMC 10 and AMC 12 tests. The AMC 10 and AMC 12 are the first in the series of tests that determines the US International Math Olympiad team. A selection of some of our favorite math-related videos from elsewhere on the internet..