It seems as though the word failure does not belong with Montessori’s theory of education. Part of the prepared environment is the opportunity to make small errors. Mistakes and failure are part of the control of error in the practical life and didactic materials. If a child does an activity and has made a mistake, the activity will show the mistake so the child can correct it.
Montessori used mistakes as a benefit to learning. If children, and even adults, can find their mistakes, they will learn from the opportunity of correcting it. Montessori students don’t have a fear of failure, it’s a way to learn.