Knots are one of the oldest techniques of mankind . Knots are connected with the development of simple tools and weapons. To tie knots is to use a so elementary cultural technique like a fire or a knife. Only through node man could make clothes. For thousands of years knots are tied and the knowledge of binding them is passed from one generation to the next.
This knowledge has been lost but in many people. The school assumes that one learns elementary nodes in the family and not in the curriculum.