In the Netherlands, a different attitude to problem-solving has been adopted. This approach, known as realistic mathematics education, is based upon Freudenthal's (1968) belief that children should be given guided opportunities to reinvent mathematics through doing it. Thus, the focus of realistic mathematics education is children's mathematisation of contexts which are meaningful to them, and through this participation in the learning process, children develop mathematical understanding and strategies. Instead of using problem-solving as a vehicle for context-based application of earlier learning as a tradition in England, realistic mathematics education uses context problems as a source for the learning process. A good example of a context building up mathematical knowledge is taking the context of a city bus. The teaching starts with a real life situation where the students have to act as the driver of the city bus. The passengers are getting on and off the bus, and at each stop the students have to determine the number of passengers in the bus. Later the same is done on paper. The development of mathematical language is elicited by the need to keep track of what happened during the ride of the bus. Initially, the language is closely connected to the context, but later on it is used for describing other situations. This way, children's conceptual understanding of related strategies from within the contexts of the problem is developed from the realistic mathematics education principle.