School mathematics is understood to be, like the discipline itself, a pure, hierarchically structured self-subsistent body of objective knowledge. Higher up the hierarchy, mathematics becomes increasingly pure, rigorous and abstract. Students are encouraged to climb up this hierarchy as far as possible, according to their ‘mathematical ability’. As they ascend, they get closer to ‘real’ mathematics, the ‘subject taught and studied at university level.
This theory is implicit in many mathematics textbooks and schemes, albeit combined with other lass purist perspectives. Thus hierarchical structures are found in many books and workcard schemes, such as the School Mathematics Project books and schemes of the 1960 and 1970s.