3-part Montessori Trays - Home School AidThree part card trays are typically used in Montessori classrooms but have become more common in other teaching methods as well. It holds 3 part cards very neatly and keeps Montessori inspired card activities well organized. The Montessori Early Childhood Three Part Card consists of three sections word, picture, and control cards. The main purpose of three part cards is to enrich your child's vocabulary. Three part cards are now commonly used