Number sense and mathematics study

Math grades tied to primitive "number sense"
Students with good "number sense" -- the innate ability to rapidly estimate the number of items in a group -- tend to earn better math grades across their academic careers, according to new research. A study involving 64 14-year-olds found that the teenagers who did well on a test that measured their "number sense" were much more likely to have gotten good grades in math classes. The researchers discovered that a child's ability to quickly estimate how many things are in a group significantly predicts their performance in school mathematics all the way back to kindergarten. "Humans actually have two separate senses of mathematics," Halberda said. "We have this intuitive sense of numbers that you and I use when we are looking at the bus, and we have a second system, which is what we use to learn in school. It relies on language, and only humans have that."
Halberda, J., & Feigenson, L. (2008, Sep. 7). Individual differences in non-verbal number acuity correlate with maths achievement Nature.