HWANG, S.; YEO, S. .; SON, T. . A Comparative Analysis of Fraction Addition and Subtraction Contents in the Mathematics Textbooks in the U.S. and South Korea. International Electronic Journal of Elementary Education, [S. l.], v. 13, n. 4, 2021. Disponível em: https://www.iejee.com/index.php/IEJEE/article/view/1438. Acesso em: 7 dec. 2024.