“…Our findings support the conclusion that children who do not yet use counting to track cardinality already understand fundamental aspects about the structure of the number system (as laid out by Barner, 2017). We know from previous research that a child who does not yet know the cardinal principle and only knows the cardinalities for a few numbers, say up to three, already knows (1) how numbers "one, two, three" go in order in the number sequence (Litkowski et al, 2020;Wynn, 1990), (2) how this number sequence can be applied to sets in the act of counting (even though they do not yet functionally understand the cardinal principle) (Gordon et al, 2019;Cheung et al, 2022, Baroody & Lai, 2022 and ( 3) how numbers "one, two, three" each represent a unique cardinality of a set one = |{a}|, two = |{a, b}| and three = |{a, b, c}| (Le Corre & Carey, 2007). Our findings together with previous research suggest they additionally have access to reasoning about set-based operations (Schneider et al, 2022a).…”