Sifting Grains: Visual Prime vs Composite Identification

This example demonstrates a sieve-style learning activity where integers are filtered and visually labeled so that prime and composite numbers become distinguishable on a coordinate plane. It centers on key number theory ideas: the definitions of primes and composites, divisibility relations, and the intuition behind the “sifting” process, supported by scatter-plot style visualization and simple statistical counting. Construction-wise, it leverages GeoGebra commands reflected in the build summary: Sequence to generate candidate integer lists, Unique to remove duplicates and keep essential values, Intersect to determine critical intersections for the geometric/visual structure, Vector (and related geometric points) to place elements in the plane, Element to fetch items from lists, and Sum to aggregate counts/indicators. Textfield/Text objects provide dynamic labeling of the current value and status, while multiple list objects (e.g., list1, list2, list3, list4, list6, list9, list10, list11) organize prime/composite groups. Buttons (start/next and controls) and a flag coordinate step-by-step animation. Suitable for upper primary through middle school, and also useful for secondary classrooms introducing prime sieving, divisibility testing, and visualization-based reasoning.