Article 1 Cardinal principle 1 Child Development 1 Child, Preschool 1 Comprehension 1 Concept Formation 1 Exact ordering 1 Female 1 Forecasting 1 Humans 1 Male 1 Mathematical Concepts 1 Number Psychomotor Performance 1 Successor function 1 Successor principle 1 child 1 child development 1 comprehension 1 concept formation 1 controlled study 1 female 1 forecasting 1 human 1 human experiment 1 individualization 1 knowledge 1 learning 1 male 1 mathematical phenomena 1