Subhankar – The Rhyming Mathematician

Subhankar Das, the Rhyming Mathematician, was a 14th-century genius who solved complex arithmetic problems orally by devising a method of rhyming, simplifying memorization of various formulae. Subhankar’s equations were known as ‘Subhankari – Manash-anka’ (mental maths) – a system of computation that allowed one to undertake arithmetic operations mentally, without the aid of pen and paper. Sadly, both his puzzles and solutions have been lost to the sands of time. Learn about the wonder that was Subhankar, the Rhyming Mathematician.

It is commonly held that Bengal experienced its golden age of education during the renaissance era. However, this is indeed a fallacious notion. The roots of education in Bengal can be traced back to the Pala dynasty in 700 CE. In truth, some historians opine that the first patshalas, a place for primary education, were established by King Dharma Pala in Bengal during 778 CE . Over time these patshalas developed and education flourished in Bengal. Having elucidated this, I shall now take you to 14^th century Bengal during the realm of Raja Banku Roy. It was during those time Bengal had seen wonders performed by a young mathematician who composed rhymes to solve mathematical problems. I present – Subhankar Das, the rhyming mathematician.

It was a sunny afternoon, the king while travelling down the road, found an exceptionally tall palm tree.The King was keen to know the height of the tree, but no one could provide a possible answer to his question. The King called for Subhankar Das who coincidentally was passing by the same road. Here it is important to mention that Subhankar had quit his job at the palace few days back, due to difference of opinion  with other officers in the palace. Subhankar, came up with the answer in no time by calculating the shadow of the tree. Such was the capability of Subhankar Das.

But what Subhankar was exceptionally good at was his capacity to solve complex mathematical problems orally. He ingeniously devised a method to simplify the memorization of various formulae required to solve arithmetic problems by rhyming. His ingenious system for performing arithmetical computations orally was dubbed ‘Shubhankari.’ Subhankar lived in an era before calculators and computers became ubiquitous tools for mathematicians. He authored a plethora of “made easy” “Arya” formulae to help children memorize and solve arithmetic problems with ease.

According to renowned linguist Dr Sukumar Sen, Subhankar had developed a process to convey complex concepts by using riddles and brief verses known as “Arya” and “Torja” in Bengali. Subhankar also wrote a book titled “Chhotrish Karkhana,” detailing the functioning of the administration during the early 18th century, when Bengal was under the rule of the Nawabs. The book comprises over two thousand shlokas that students would memorize, known as “Shubhankari.” Let us look at one such rhyme to solve a problem by Subhankar Das.

“Tireesh hath brikkha ek chhilo uchcho sthane,

Churaay uthibe ek keet koray monay,

Diba bhage dosh haath uthite lagilo,

Nisha joge ashto haath neechete namilo

Na paaye jaabat chura kore say aton

Kato diney uthechhilo karo nirupon”

(There was a 30-hand high tree on an elevated land and an insect decided to reach the top of that tree. Every morning it managed to climb 10-hand but as night descended, he slumped eight-hand downwards. But the insect had vowed to complete his journey. How many days did it take for him to reach the top?)

The rhyme calculates it this way, the insect had ascended two hands, taking into account both its ascent and descent rate. As it did approach the conclusion of its journey, it was able to traverse 10 hands during the daylight hours. Thusly, the residue of the ascent, that is to say the remaining 20 hands of height, were surmounted in the course of 10 additional days.

Here’s another problem:

‘Sarobare bikashito kamal nikar

Madhulobhe elo tatha onek bhromor,

Proti padme boshi bhromor jugol

Oliheen rahe tobey ekti komol

Ekek bhromor boshe prottek kamole

Baki rohe ek oli, sankhya deho boli’

(Lotus flowers have bloomed in a pond. Seeing this, bees trooped in humming. If each pair of bee sits on each lotus but one lotus remains empty. But if one bee sits on each flower then one bee doesn’t get a flower to sit on. The question then is, how many bees were there and how many lotuses were there)?

If we try to solve this equation taking help from algebra, this is how we will find out: Let us take the number of flowers as X and number of bees as Y

Y = 2 (X -1)…..1

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Y= X +1……2

We solve (1) and (2) and get

X=3,

Y= 4

So, the answer is, there were three lotuses in the pond and four bees.

In the beginning, the formulae of Subhankar were lauded and held in high regard for their capacity to provide an uncomplicated means of solving intricate calculations. However, with the passage of time, their interpretation took a negative turn, and they were viewed as an instant resolution to mathematical conundrums. These equations, which he derived, were known as ‘Manash-anka’ (mental maths) – a system of computation that allowed one to undertake arithmetic operations mentally, without the aid of pen and paper.

Sadly, both his mathematical puzzles and their solutions have been lost to the sands of time, and even his name has vanished into oblivion. This great son of Bengal remains confined within ancient arithmetic textbooks and the barrage in Bankura (Subhankar Danra) that bears his name.

Sources : Kolkata TV (Bharoth amar Bharotborsho)                                         

                   getbengal.com

                   Paper by Peu Banerjee published in International Journal of
Architectural Heritage