This study investigates when young children develop the ability to map between three numerical representations: arrays, spoken number words, and digits. Children (3, 4, and 5 years old) had to map between the two directions (e.g., array-to-digit vs. digit-to-array) of each of these three representation pairs, with small (1–3) and large numbers (4–6).

Five-year-olds were at ceiling in all tasks. Three-year-olds succeeded when mapping between arrays and number words for small numbers (but not large numbers), and failed when mapping between arrays and digits and between number words and digits. The main finding was that four-year-olds performed equally well when mapping between arrays and number words and when mapping between arrays and digits. However, they performed more poorly when mapping between number words and digits. Taken together, these results suggest that children first learn to map number words to arrays, then learn to map digits to arrays and finally map number words to digits. These findings highlight the importance of directly exploring when children acquire digits rather than assuming that they acquire digits directly from number words.