Improving the quality of education is an important ambition of educational policy. The TAL project aims to contribute to this. It is a project initiated by the Dutch Ministry of Education, Culture and Science, and carried out by the Freudenthal Institute (FI) of Utrecht University and the Dutch National Institute for Curriculum Development (SLO), and partly conducted in cooperation with the Rotterdam Center for Educational Services (CED). The quality of education can be improved in many ways. TAL proposes to do this by providing insights into the broad longitudinal outline of the learning-teaching process and its internal coherence. The intention of TAL is to give support to teachers in combination with the guidance they get from mathematics textbook series. This learning-teaching trajectory description for measurement and geometry aims to succeed in stimulating classroom practice and to inspire teachers to didactical efforts on a high level, in what was up to now, in the lower grades of primary school, a less-known subdomain of mathematics. The learning-teaching trajectory with intermediate attainment targets offers support to teachers, in order to give measurement and geometry a full and worthy place within the mathematics curriculum. For that to be the case, the foundation that is made with this learning-teaching trajectory must be built upon in the higher grades of primary school and beyond.