Here is a summary of the document in 3 sentences or less: [SUMMARY] The document analyzes how the ideals of the Modern Mathematics Movement circulated and were appropriated in primary education in Brazil and Portugal based on articles published in pedagogical journals from 1955 to 1985. It finds that the journals promoted a view of mathematics based on set theory and mathematical logic with an emphasis on symbolic language and methodological aspects, and supported teaching based on Piaget's theories of cognitive development. While the journals differed between countries, they contributed to spreading conceptions aligned with mathematics education reformers to help teachers educate children.