Previous studies in a variety of countries have shown that there are
substantial individual differences in children’s spontaneous focusing on
numerosity (SFON), and these differences are positively related to the
development of early numerical skills in preschool and primary school. A
total of 74 5-year-olds participated in a 7-year follow-up study, in
which we explored whether SFON measured with very small numerosities at
5 years of age predicts mathematical skills and knowledge, math
motivation, and reading in fifth grade at 11 years of age. Results show
that preschool SFON is a unique predictor of arithmetic fluency and
number line estimation but not of rational number knowledge,
mathematical achievement, math motivation, or reading. These results
hold even after taking into account age, IQ, working memory, digit
naming, and cardinality skills. The results of the current study further
the understanding of how preschool SFON tendency plays a role in the
development of different formal mathematical skills over an extended
period of time.