82 books • 14 series
Breakthroughs in Math, Book 1
Book #2: Breakthroughs in Math, Book 2
Book #1: Math Skills That Work
Book #3: Number Power 3
Book #1: Geometry
Book #1: Graphs, Tables, Schedules & Maps
Book #8: Sympathy and the State in the Romantic Era
Book #2: Skills That Work