WASHINGTON: Gaurav Raja, a 15-year-old Indian American high school student, has memorised 10,980 digits of pi, a mathematical term representing the ratio of a circle's circumference to the diameter, to break a North American record.

His math and computer science teacher at Salem High School in Virginia had challenged her students to memorise at least 40 digits of pi, a non-repeating decimal that has no end, more accurately expressed as a fraction, 22/7.

But Gaurav decided to go a step further and broke the 27-year-old North American pi memorisation record of 10,625 digits set by David Fiore of Swiftwater, Pennsylvania, to take a place among the top 10 in the world. Hiroyuki Goto of Japan set the world record in 1995 by memorising 42,195 digits of pi.

Gaurav, who wants to be a video-game programmer, can't explain how he memorised such a big slice of pi. He just did it. "I don't see anything in my head. It's just kind of there," he said.

"It just flows, I guess. I found a Web site that had the records, and I decided, 'Let’s try to get a ranking on here,'" he said, referring to the Web site www.pi-world-ranking-list.com.

Gaurav has demonstrated a capability for memorisation before. In March, he rattled off 8,784 digits of pi.

One weekend, he memorised the capital of every country in the world, said his father, Jogesh Raja. Gaurav's next project is memorising the names of all the winners of the Nobel Prize.