ULU, M.; ÖZDEMIR, K. Determining the Mental Estimation Strategies Used by Fourth-Grade Elementary Students in Four Basic Mathematical Operations. International Electronic Journal of Elementary Education, [S. l.], v. 11, n. 1, p. 63–75, 2018. Disponível em: https://iejee.com/index.php/IEJEE/article/view/548. Acesso em: 13 dec. 2024.