The National Assessment of Educational Progress (NAEP) 2005 assessment was administered to a stratified random sample of fourth-, eighth-, and twelfth-graders at the national level and to a stratified random sample of fourth- and eighth-graders at the state level. The Mathematics Framework for NAEP was revised in 1996 and again in 2005. The new framework reflects current curricular emphases and objectives, while continuing a connection to previous frameworks. The NAEP Mathematics Framework describes content in five strands and the percentage of questions that should be devoted to each. The Mathematics Framework for NAEP 2005 also describes three levels of mathematical complexity that include aspects of knowing and doing mathematics. Approximately half of the score on the assessment is based on items of moderate complexity, with the remainder of the score based equally on items of low and high complexity. This document presents a sampling of variables and factors of the NAEP grades 4 and 8 Mathematics Assessment for Colorado in 2005, including: (1) Trends in Average Scale Scores line Graphs; (2) Stem and Leaf Tables Comparing Colorado to All Other States and the Nation; (3) Maps for Average Scale Score; (4) Bar Graph Results by National School Lunch Eligibility and Race/Ethnicity; (5) Description of Geographic Locations; and (6) Bar Graphs by Location.