Assess students' ability to analyze and generate every distinct part–part–whole decomposition for each whole number from 1 to 10 using manipulatives, number-bond diagrams, drawings, and addition equations. Tasks: enumerate all unique unordered part pairs for each whole (acknowledging commutativity), represent each decomposition concretely and pictorially, record corresponding equations, justify completeness of lists, detect and explain patterns across numbers (e.g., counts and symmetry), and convert between representations. Designed for Pre-K–Grade 2 with advanced analytic challenge: include identifying missing decompositions and explaining reasoning.