However, this correlation does not appear to apply to subtraction and division, researchers said. (Agencies)
'Grey' cells process information in the brain and are connected via neural pathways, the tracts through which signals are transferred.
Neural pathways are comparable to a bundle of cables. These cables are surrounded by an isolating sheath: myelin, or 'white matter'.
The thicker the isolating sheath and the more cables there are, the more white matter. And the more white matter, the faster the signals are transferred, said educational neuroscientist Bert de Smedt, Faculty of Psychology and Educational Sciences, KU Leuven in Belgium.
While the correlation between arithmetic and white matter tracts linking certain brain regions is known, very little research has been done to test this correlation in normally-developing children.
In the new study, researchers had 25 children solve a series of different arithmetic operations while undergoing a brain scan. They then compared the quality of the children's white matter tracts with their arithmetic test performance.
"We found that a better quality of the arcuate fasciculus anterior - a white matter tract that connects brain regions often used for arithmetic - corresponds to better performance in adding and multiplying, while there is no correlation for subtracting and dividing," said de Smedt.
"A possible explanation for this is that this white matter bundle is involved in rote memorisation, whereas when we subtract and divide, such memorisation plays less of a role.
"When subtracting and dividing we are more likely to use intermediary steps to calculate the solution, even as adults," he added.
These findings also add insight into the link between reading and arithmetic, said de Smedt.
"Reading proficiency and arithmetic proficiency often go hand-in-hand. The white matter tract that we studied also plays an important role in reading: when we learn to read, we have to memorise the correspondence between particular letters and the sound they represent.
"It is likely that a similar process occurs for addition and multiplication. Just think of the notorious times-table drills we all memorised as schoolchildren; it is almost like learning a nursery rhyme. Some of us can even auto-recall these sums," de Smedt said.
"This also might explain why we often see arithmetic problems in children with dyslexia. Likewise, children with dyscalculia often have trouble reading," he said.
However, this correlation does not appear to apply to subtraction and division, researchers said.