Number Sense Growth in Kindergarten: A Longitudinal Investigation of Children at Risk for Mathematics Difficulties


  • This study was supported by a grant from the National Institute of Child Health and Human Development (R01 HD36672). We are extremely grateful to the children and teachers who participated in the project.

concerning this article should be addressed to Nancy C. Jordan, School of Education, University of Delaware, Newark, DE. Electronic mail may be sent to


Number sense development of 411 middle- and low-income kindergartners (mean age 5.8 years) was examined over 4 time points while controlling for gender, age, and reading skill. Although low-income children performed significantly worse than middle-income children at the end of kindergarten on all tasks, both groups progressed at about the same rate. An exception was story problems, on which the low-income group achieved at a slower rate; both income groups made comparable progress when the same problems were presented nonverbally with visual referents. Holding other predictors constant, there were small but reliable gender effects favoring boys on overall number sense performance as well as on nonverbal calculation. Using growth mixture modeling, 3 classes of growth trajectories in number sense emerged.