How do you describe mathematics tasks?

[First paragraph] What do you think of the task in figure 1? Would you use it with learners? How would you describe it? Many different adjectives are used to describe mathematics tasks, such as “rich”, “open”, “inquirybased”, “procedural”, and so on, but what do they mean? Do teachers understand them in broadly similar ways or in a variety of different ways? The English national curriculum suggests that learners should be offered “rich and sophisticated problems” (DfE, 2014, p.3). But what does that mean? In a recent piece of research (Foster & Inglis, 2017), we carried out two studies to investigate how mathematics teachers use adjectives to describe mathematics tasks.