Montessori programs aimed at preschool and Kindergarten- aged children allow young learners to choose which “tasks” or activities interest them. These tasks centre around special Montessori puzzles -- the essential features of these puzzles being they contain a “right answer” and allow for self-correction. A strong emphasis is therefore placed on learning being concrete and rooted in practical experience, along with children developing a sense of self-sufficiency and confidence. Specially trained teachers act as guides, introducing children to progressively more difficult materials when appropriate. A Montessori classroom is typically very calm and orderly, with children working alone or, sometimes, in small groups.