This suggests that reasoning about how number words encode exact quantities and how numbers relate to exactly equal sets emerges after learning to count. Exciting questions remain about how such learning happens! (4/4)

But children who can make this inference might not do so based on exact equality: they sometimes assign the same number word to two sets that are approximately equal, but differ by just 1 item❗(3/4)

Children who can count and construct large sets (CP-knowers in the literature) can infer the quantity of a hidden set from a set that appears equal, but children who only know small number words (subset-knowers) cannot 🧒 (2/4)