Lesh, R., Post, T., & Behr, M. (1988). Proportional Reasoning. In J. Hiebert & M. Behr (Eds.) Number Concepts and Operations in the Middle Grades (pp. 93-118). Reston, VA: Lawrence Erlbaum & National Council of Teachers of Mathematics.
Star, J. R., Caronongan, P., Foegen, A., Furgeson, J., Keating, B., Larson, M. R., Lyskawa, J., McCallum, W. G., Porath, J., & Zbiek, R. M. (2015). Teaching strategies for improving algebra knowledge in middle and high school students (NCEE 2014-4333). Washington, DC: National Center for Education Evaluation and Regional Assistance (NCEE), Institute of Education Sciences, U.S. Department of Education.
NOTE: the resource marked with an asterisk is an excerpt from the report College and Career Readiness Standards for Adult Education (U.S. Department of Education, Office of Vocational and Adult Education). Download the full report here.
New to the College and Career Readiness Mathematics Standards for Adult Education?
Donna Curry of the SABES PD Center for Mathematics and Adult Numeracy/Adult Numeracy Center at TERC gives an overview in this video.
Building a Curriculum orientation video
Donna Curry of the SABES PD Center for Mathematics and Adult Numeracy/Adult Numeracy Center at TERC gives an overview in this video.