AoPS 2-Book Set : Art of Problem Solving Beast Academy 3A Guide and Practice 2-Book Set : Beast Academy 3A covers : Angles, triangles, quadrilaterals, other polygons, puzzles with polyominoes. Patterns with repeated addition, arithmetic sequences, foundations for understanding multiplication, distribution, and factoring. Perimeter and Perimeter and area of rectangles, polygons, and rectilinear shapes. Horrible Ray endorses the Art of Problem Solving Beast Academy 3A Guide and Practice 2-Book Set for 3rd Grade and up. Horrible Ray, Horrible Books, Horrible University