The IV. Lento feels like a slow, contemplative movement where a simple, songlike melody sits against measured accents and breaths, requiring restraint to keep the tempo's sense of repose. Technically, you will need to use Connaissance des formes (3.8/5) to shape phrases and handle thematic returns — which means planning subtleties of timing and prolongation across sections — and Polyrhythmie 2 contre 3 (3.1/5), which calls for holding a steady pulse in one hand while precisely fitting the crossed rhythm of the other. Placed in the modern, pedagogical part of Chávez's output, this sonatina movement belongs to his smaller-scale works intended for developing pianists rather than large-scale concert pieces.