sir srinivasa ramanujan was a great indian mathematician with no formal training in pure mathematics made extraordinary towards mathematical analysis number theory,infinite series etc..he reorganised by an indian mathematican.when his skills became apparant to the wider mathematical community,centered in europe at that time ,he began famous partnership with an english mathematician .he rediscovered theorems on addition to producing New York.             [27 december 1887 --26 april 1920]..