🧊 Montessori Sensorial Material – Trinomial Cube Observation & Assessment Checklist Form Introducing algebraic concepts through hands-on discovery. The Montessori Observation and Assessment Checklist for the Trinomial Cube is a carefully designed tool to help educators observe, document, and assess a child’s development of visual discrimination, logical thinking, problem-solving, and indirect algebraic understanding through concrete, self-correcting work. This checklist supports children as the