Why is National Mathematics Day celebrated on December 22? 
National Mathematics Day is celebrated on December 22, since 2012, after former Prime Minister Manmohan Singh made the declaration, to pay tribute to S Ramanujan and celebrate his birth anniversary. Ramanujan is known for his contributions to the theory of numbers and compiling over 3,000 mathematical results and equations. Notably, his 129th birth anniversary was observed on the day.
A self-taught mathematician who made extraordinary contributions to the world of mathematics, S Ramanujan was one of the most influential mathematicians of his time. He was born on December 22, 1887 into a Tamil brahmin Iyenger family in Erode, Madras Presidency. His father hailed from Thanjavur district, and worked as a clerk in a sari shop. From compiling over 3900 mathematical results and equations to getting discoveries named after him, his numerous assertions in mathematics opened up new vistas of mathematical research. Mentored by GH Hardy, an English mathematician, Ramanujan even has a prime number named after him widely known as 'Ramanujan Prime' which is related to prime-counting function. 