2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/67900We give elementary and short proofs of the Littlewood-Richardson rules for type A Grassmannians and maximal isotropic Grassmannians, based on the corresponding Pieri rules.9 pages, LaTeX2e, to appear in Advances in MathematicsCombinatoricsAlgebraic Geometry05E15 (Primary) 14M15 (Secondary)text