Maths whizz Andy comes fifth place in championships
HE’S the Welsh maths whiz who can multiply two eight-digit numbers, tell you the day of the week of any date from 1600 to 2100 and calculate the square root of a six-digit number – all in his head.
And now Andy Robertshaw has proven he’s a brainbox on the global stage – by coming fifth in the Mental Calculations World Championships.
Andy, from Bridgend, took on top maths brains as part of the Mind Sports Olympiad, and is currently preparing for the Mental Calculation World Cup in Germany later this month.
In the gruelling contest, Andy will be challenged to:
Add two numbers consisting of 10 digits each, 10 times in 10 minutes;
Multiply two eight-digit numbers by each other, 10 times in 15 minutes;
Find the square route of a random six-digit number 10 times in 15 minutes to the nearest eight decimal places; and
Find the day of the week for 50 random dates between the years 1600 and 2100 within one minute.
Competitors are not allowed to use a calculator or even a pen. Everything must be done in their heads. The only thing they can write down is the answer. Some contestants run foul of the rules.
Andy said: “In the last competition a person was penalised for rewriting the question with the numbers on top of each other instead of side by side. It does make it easier but I thought it was bit harsh – but I suppose rules are rules.
“I try and be methodical, I don’t go for speed, I go for accuracy and try not to panic. The competition in Germany gives you a surprise round where there are maths problems you have two minutes to solve.
“I am a good mathematician so tend to do well on that part. I am quite busy and don’t have much time to prepare for the competitions so I like the surprise ones because it makes it a level playing field.”
Unsurprisingly, his top subject in school was maths and he went on to achieve a PhD in a branch of mathematics called graph theory at Nottingham University.
Meanwhile Andy, a credit risk manager, says he has different techniques depending on the type of calculation.
“For addition I do what you are taught in school but instead of doing the hundreds, tens and units individually I do two at a time and hold it in my head” said Andy.
“For the dates I use a technique called the Doomsday Algorithm. It takes advantage of each year having a certain day of the week (the doomsday) upon which certain easyto-remember dates fall like fourth of the fourth and sixth of the sixth.”