The basic math skill, number system knowledge, is the ability to relate a quantity to the numerical symbol that represents it, and to manipulate quantities and make calculations.
This skill is the basis for all other mathematics abilities, including those necessary for functioning as an adult member of society, a concept called numeracy.
"An early grasp of quantities and numbers appears to be the foundation on which we build more complex understandings of numbers and calculations," said Kathy Mann Koepke, Ph.D., director of the Mathematics and Science Cognition and Learning: Development and Disorders Program at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).
The researchers also evaluated such cognitive skills as memory, attention span, and general intelligence.
The researchers found that by seventh grade, children who had the lowest scores on an assessment of number system knowledge in first grade lagged behind their peers.
For the testing at age 13, 180 of the students took timed assessments that included multiple-digit addition, subtraction, multiplication, and division problems; word problems; and comparisons and computations with fractions.
The researchers' analysis showed that a low score on the assessment of number system knowledge in first grade significantly increased a student's risk of getting a low functional numeracy score as a teenager.
The researchers examined learning and found that first graders with the lowest scores also had the slowest growth in number system knowledge throughout that school year. Starting with poor number knowledge can put children so far behind that they never catch up, the researchers said.
The study has been published online in the journal PLoS One.