To help teachers in comparing the content of their instruction with the content of standardized tests, a taxonomy of elementary school mathematics was developed. The taxonomy consisted of matrix with three dimensions; (1) mode of presentation (how questions are asked); (2) nature of material (type of numbers or mathematical terms); and (3) operation (process required). The intersection of these three dimensions resulted in a matrix of 468 cells, each cell representing a topic that a teacher may elect to cover. The taxonomy was applied to the four most popular standardized tests of mathematics: the Stanford Achievement Test (SAT); the Iowa Tests of Basic Skills (ITBS); the Metropolitan Achievement Tests (MAT); and the Comprehensive Tests of Basic Skills (CTBS). Because of the striking differences found between the four tests, teachers should deliberately select tests which best match the existing curriculum and/or reappraise the curriculum in terms of its match with test content. This match is crucial for diagnosing achievement gains and instructional strengths and weaknesses. (Author/CP)