About Visible & Tangible Math
This approach to teaching mathematics is called Visible & Tangible Math because of the use of color-coded Algebricks rods (a.k.a. Cuisenaire rods) that allow students to see, feel, and experiment with mathematical concepts.
Booklet
Videos
A 1961 film from the National Film Board of Canada. Caleb Gattegno uses Cuisenaire Rods to help young children intuitively understand mathematical concepts. Really amazing!