Thirty years of research: interpretations of the equal sign in China and the USA.

This study examined students' conceptions about the equal sign in light of historical findings with an international comparison group. Textbooks for preparation of students as mathematics teachers were examined. Participants were sixth-grade students from the USA (n = 105) and China (n = 145). About 98% of the Chinese children correctly answered all items by providing conceptually accurate explanations, but only 28% of the U.S. sample did. Textbooks for education majors who would teach in the USA rarely discussed the equal sign as equivalence while the Chinese texts introduced the "equal sign" in a context of relationships and discussed it as "balance," "sameness," or "equivalence."