This report provides a detailed analysis of skill complexes in the multi-year sequence of arithmetic and general mathematics that are covered in school textbooks prior to the beginning of formal algebra. The analysis is organized to show the shape of the learning opportunity that most students are likely to get in school by about the time they reach the end of grades 1-8. The focus is on the mathematical tasks that students do, and in particular what they do today so that improvements in learning opportunities can be designed. Students mainly get opportunities to learn how to do things in mathematics, rather than to understand mathematical meaning. Similarities in content across textbooks for the same grade level are far more striking than the differences, but there are real differences in the way many topics are presented, and in the sequencing of topics during the year. There seems to be much consensus regarding what schools can, or at least do, accomplish. The report then briefly highlights the follwoing topics: whole numbers, computation with whole numbers, common fractions, decimals, percent, ratio and proportion, probability and statistics, integers, algebra, geometry, measurement, and special topics, each with subtopics. (MNS)