Alexis Lemaire is a member of an elite group of people known as "human calculators"- people who can perform amazing mathematical feats without the use of a calculator.

There are only about two dozen people in the world who qualify for this Title.They all do different things - one is an expert at adding a number to itself more times in 15 seconds than a person can do it with a calculator, another multiplies eight-digit numbers faster than anyone else in the world.

Alexis's expertise is to find the 13th root - he started with calculating the 13th root of a randomly selected 100-digit number, and has now moved onto 200-digit numbers. In fact, he holds the record for calculating the 13th root of a 200-digit number in 77.92 seconds (the answer was 2396232838850303 - the original number extended for six lines!).

The root of a number is a number which, multiplied by itself, gives you the original number - for eg: the square root of 25 is 5 (5x5) or the 16 is 4 (4x4). Alexis goes one step further - he finds the 13th root - which means that the number needs to multiply by itself 13 times to get to the final number.

Just like athletes have to train for their sport in order to excel, these "mathletes" also have to train their brains. Alexis trains for about four hours a day doing random calculations and memorizing sequences of numbers.

Alexis's ambition is to continue to improve his speed on the 13th root, learn between 39 -100 foreign languages, but most of all do the biggest multiplication calculation ever attempted.

His advice to kids who want to be "human calculators - drink only water and do not eat any junk food, because the brain performs badly on too much sugar!