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Students show deficient understanding on fraction division and supporting that understanding remains a challenge for mathematics educators. This article aims to describe primary students’ understanding of partitive fraction division (PFD) and explore ways to support their understanding through the use of sequenced fractions and context-related graphical representations. In a design-research study, forty-four primary students were involved in three cycles of teaching experiments. Students’ works, transcript of recorded classroom discussion, and field notes were retrospectively analyzed to examine the hypothetical learning trajectories. There are three main findings drawn from the teaching experiments. Firstly, context of the tasks, the context-related graphical representations, and the sequence of fractions used do support students’ understanding of PFD. Secondly, the understanding of non-unit rate problems did not support the students’ understanding of unit rate problems. Lastly, the students were incapable of determining symbolic representations from unit rate problems and linking the problems to fraction division problems. The last two results imply to rethink unit rate as part of a partitive division with fractions. Drawing upon the findings, four alternative ways are offered to support students’ understanding of PFD, i.e., the lesson could be starting from partitive whole number division to develop the notion of fair-sharing, strengthening the concept of unit in fraction and partitioning, choosing specific contexts with more relation to the graphical representations, and sequencing the fractions used, from a simple to advanced form.

Work‐sampling studies are typically applied to determine unit rates (a measure of construction labour productivity) for labour‐intensive building construction processes. This study analyses how this methodology can be adapted for application to labour‐intensive tunnelling processes, e.g. the construction of the inner lining. Therefore, first, the application of the work‐sampling methodology for typical building construction process (wall formwork processes for a classical reinforced concrete building structure) was analysed. On this basis, a detailed work‐sampling study for constructing the inner lining of a railway tunnel was prepared and performed. Thereby, the usage of a tablet computer was tested instead of analogue execution with paper forms. The study demonstrated that work‐sampling studies allow the determination of average unit rates of tunnelling processes (for specific project and construction properties). Furthermore, the methodology allows to identify detailed unit rates with the goal to demonstrate specific influences (e.g. disturbances), which can be further utilized in construction and site management as well as claim management processes, such as the determination of productivity losses. However, the double analysis carried out for the tunnel inner lining (reinforcing and tunnelling workforce) and the size of the analysed workforces (up to ten workers) showed the limits for a one‐person work‐sampling study. [ABSTRACT FROM AUTHOR]