First, each unit is a complete qualification in its own right; each is narrowly focused, with the emphasis on depth, rather than breadth, of study.
Second, each unit can be studied to fulfil an immediate mathematical need, either as additional support for other courses, or to consolidate mathematics learned, but not fully assimilated.
Third, portfolio work should be directed at other areas of students' study.
This twin track approach to assessment, with the portfolio being devoted to applications of the mathematics and the written examination testing the principles of the unit, makes these qualifications different from others.
The units' attractions for science students are apparent. Students will gain a qualification; they will learn mathematics to support and enhance their science and they can apply the maths to science investigations as part of their assessment.
Finally, your cryptic headline implies that a C grade pass in GCSE mathematics is worthless. While achieving grade C may be insufficient to enable a student to cope with the demands of A-level science courses, for those not pursuing subjects which have a strong mathematical slant, such a pass is entirely adequate as a baseline of achievement at age 16-plus.
Jack Abramsky Principal subject officer for mathematics QCA 29 Bolton Street, London W1Y