“…If students have already been taught prime factorisation, they will be able to find the lowest common denominator using prime decomposition. However, curriculums vary around the world (e.g., Lee, DeWolf, Bassok, & Holyoak, 2016;Zhou, Peverly, & Xin, 2006), and the presentation of fractions also varies across textbooks within each country (e.g., Cady, Hodges, & Collins, 2015;Vasconcelos et al, 2017). Thus, we cannot assume that most elementary students will have learned this method.…”