Mediterranean Journal for Research in Mathematics Education Vol. 10, 1-2, 187-213, 2011 An International Perspective between Problem Types in Textbooks and Students’ Understanding of Relational Equality ROBERT M. CAPRARO: Texas A & M University & Aggie STEM Center MARY MARGARET CAPRARO: Texas A & M University & Aggie STEM Center EBRAR Z. YETKINER: Texas A & M University SENCER M. CORLU: Texas A & M University SERKAN OZEL: Bogazici University, Istanbul, Turkey SUN YE: West Virginia University HAE GYU KIM: Jeju National University, Jeju-do, Republic of Korea ABSTRACT: This study broadens the international knowledge base about second- and sixth-grade students' understanding of the equal sign and possible explanatory power of their textbooks affording insights about educationally relevant factors related to the presentation of the equal sign. Participants from China (Beijing, Xia Peng) , S. Korea (Jeju) , Turkey (Istanbul) , and the U.S. (central Texas) (N = 1823) were administered a language-free instrument to determine their conceptualization of the equal sign. Textbooks used by each sample were coded for presentation of the equal sign. Results showed “operation equals answer” in S. Korean second- and sixth-grade textbooks (18%, 16%) was substantially lower than in Chinese (41%, 28%), Turkish (40%, 27%), and central Texas textbooks (54%, 18%), respectively. The achievement of students from Beijing and Jeju was substantially higher than the students from Istanbul and central Texas. The results from the equal sign instrument are discussed in relation to the presentation of equal sign in the textbooks. Key words: Equal sign, International comparisons, Elementary mathematics, Early algebra. THEORETICAL BACKGROUND In this study, the connection between textbook use and conception of the equal sign is examined on a basis firmly rooted in international mathematics achievement and curricula comparisons. While international comparisons are useful as benchmarks to measure progress and change as new innovations are implemented, their most important application is to explore what mathematics is taught and how it is taught across countries. This study contributes uniquely to the literature by examining student