Scientists have for the first time established a link between a primitive, intuitive sense of numbers and performance in math classes, a finding that could lead to new ways to help children struggling in school.

A study involving 64 14-year-olds found that the teen-agers who did well on a test that measured their “number sense” were much more likely to have gotten good grades in math classes.

“We 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,” said Justin Halberda, an assistant professor at Johns Hopkins University who led the research, published online this week by the journal Nature. “It was very surprising.”

Researchers have long known that people are born with the ability to quickly estimate relative numbers of objects, with studies finding the skill in children within months of being born and across cultures. It is what people use in day-to-day life to estimate everything from whether a stack of paper plates will suffice for a barbecue to whether they have picked the best spot to squeeze onto a crowded train.

“It’s what you and I use when we’re getting on a bus and trying to figure out which door to go through,” Halberda said. “We quickly scan the bus to see if there are more people on the front of the bus or the back of the bus.”

Every animal tested has been found to have a number sense, including monkeys, pigeons and even rats, indicating that it is an ancient cognitive skill that evolved early. Such an ability would be crucial, for example, for rats assessing which trash can tends to yield the most scraps or for a chimp deciding whether to flee or attack an aggressor.