This article examines the design of the mathematics curriculum applied in Sweden between 1980 and 1995 and how this design affected student results between two international tests, SIMS1980 and TIMSS1995. During this period, the results in mathematics improved on a general level, but in some topics it did not. The results increased significantly in arithmetic, but very little in algebra. I investigate in what respect the arithmetic and algebra curricula were designed differently. The analysed materials are syllabus, commentary material, tests, and textbooks. The analysis is based on Bernstein’s theory on classification and framing. The main conclusion is that strong framing in the curriculum can be associated with better student results in TIMSS and evidence for a causal relation between these entities is presented. On the basis of my finding, I raise a critical question about the change in governing policy that took place in Sweden between 1975 and 2000.