Very easy to understand-- I may go back and check to see what other graphics he has available. It actually applies to PC's too, but the graphics would look just a little different.
Teachthought describes this as "While the site is simple a crudely interactive graphic with links to videos, it has, in one fell swoop, creatively curated some of the most compelling and engaging "problems" in mathematics. From Benford's Law to French Numbers, to whether or not zero is an even number, it frames the content area of math-which is often riddled with rote practice of very traditional arithmetic and formulas-in a problem-based learning kind of approach.
Fantastic resource for bell ringers, test questions, math project-based learning ideas, or as a model for students to curate their own curiosities about the incredible-and poorly marketed-world of mathematics."
Pages and pages of resources and tools that you can use. For example, the language arts teaching tools page has many graphic organizers and other useful sites.