“One, two, three, four…” N. Sudhakaran recites in Malayalam. It is a rhyme from his first book – a book of mathematical rhymes for children, published in 1985. Since then he has written 60 children’s books on recreational mathematics, mostly on puzzles.
Once he starts on them, there is no stopping him as he begins explaining different puzzle sets and tools that he has made over the years. From a cardboard box, he takes out a set of bent metal rods with knots at a quarter of their lengths. He tangles them and hands it over to me. “Try this one out. It is called the ‘Bent nail puzzle’. All you have to do is unknot it,” he suggests with a naughty smile. I sweat it out for several minutes in vain. After a while I give it back. Sudhakaran takes it, dabbles with it for a moment and separates the two rods easily.
For this retired LIC employee, residing at Mannanthala, there is no greater pleasure than working on tough mathematics puzzles, tricks and games.
“My love for mathematics comes from my mother. She used to make me count. I was the one who counted all the coconuts that we collected from our grove, before selling them,” recalls Sudhakaran. But his love for puzzles began during his days in Maharaja’s College, Kochi, where he did his undergraduate studies in Mathematics. He couldn’t finish the course. But at the age of 79, he is an expert on various mathematical puzzles, tricks, magic square variants and games.
N. Sudhakaran’s ‘Ksheerabala’ puzzle
Another puzzle involves fitting one more bottle into a rectangular space that already holds tightly packed 40 bottles. For convenience’s sake Sudhakaran uses small PVC pipe pieces instead of bottles. He tells me not to attempt it. “It’s a tough one to figure out if you are not familiar with such puzzles. I have named it ‘Ksheerabala’, after the Ayurvedic medicinal ghee that you are supposed to take for 41 days. I have also made an 83-bottle version of the same puzzle,” he says.
Although a puzzle-lover since his college days, Sudhakaran began actively collecting puzzles, make his own versions and write books on them from 1985 onwards, after becoming a member of the Kerala Shastra Sahithya Parishath. He has made models for over 1,800 puzzles till date. Sudhakaran says, “I have collected it from different sources over the years. My son Baiju, who works in the United States, has brought me a lot of books from there. I got several puzzles from street-sellers. I have also learned a lot from renowned mathematics writer Martin Gardner’s writings on recreational mathematics in Scientific America magazine.”
Quadratic equation slide rule invented by N. Sudhakaran
Sudhakaran’s collection doesn’t end with puzzles alone. He also makes scientific gadgets and tools. He has made a special version of abacus for easier calculation with Indian numerals. “It has a single slanted deck with nine beads on each wire. I call it ‘Subacus’, ” says Sudhakaran. One of his original inventions is a version of the, now obsolete, slide rule that can be used to solve quadratic equation with integer solutions using the coefficients alone, without doing any calculation.
N. Sudhakaran demonstrating the ‘Obedient coconut of Kerala’ set-up which shows how friction works
‘Obedient coconut of Kerala’ is another captivating scientific model Sudhakaran has made. It involves a sphere-like weight made of two coconut shells with a larger rubber ball stuffed inside, with a thread passing through it. When you hold the two ends of the thread, vertical and taut, the weight won’t move down. “The thread doesn’t pass right through the rubber ball. It goes around it, jammed in between the ball and the shell. It will only move down when the thread is relaxed and friction is less. A team of experts from UNICEF who came to visit me, after seeing my works at some expo in Delhi, was bowled over by this particular set-up of mine,” he says. Sudhakaran won the Kerala State Council for Science, Technology and Environment’s award for children’s literature in 2009 for his book Shastra Pareekshanangal Kuttikalkku .
N. Sudhakaran with the Clinometer he made
Although he loves making equipment like clinometer, telescope and periscope, recreational mathematics remains his passion. He is often invited to schools to train students as well as teachers in puzzles and mathematical games. “Nowadays there are institutes solely dedicated to teach children how to use the abacus. Abacus can be taught to kids in just three days,” says Sudhakaran. He believes that teaching maths through puzzles, tricks and games can go a long way in helping children learn mathematics easily.
