British actor Dev Patel tackles numbers and formulas in "The Man Who Knew Infinity", a biopic looking at the life of Indian mathematician Srinivasa Ramanujan.

The drama follows the journey of the Indian accounting clerk, who was brought to England before World War One by Cambridge University professor Godfrey Harold Hardy (Jeremy Irons), as he seeks to prove himself and his theorems.

Patel, who admits he is "terrible" at maths, said in an interview the role was both challenging and emotional.

"It's daunting but actually when you read the script, it was a very emotional read ... It was actually a very triumphant story for me, a very enlightening film and I wanted more people to know about it, because I didn't know about this incredible man," he said.

"If I could help breathe life into his legacy, then I was happy to do so and that's what we did."

In the movie, which also stars British actor Toby Jones and writer and comedian Stephen Fry, Patel's character faces challenges such as racism, rejection and serious illness.

The 25-year old, known also for "The Best Exotic Marigold Hotel", said he was able to base his portrayal on photographs of the mathematician and his notebooks.

"There was no real physical material that we could mimic, there was no found footage or anything of how he spoke. You know, the cliché is a picture says a thousand words, but it really is true," he said.

"We tried to capture the essence of this man and his resilience that you could see in the pictures, you could read in the book. He's fiercely passionate and that's something I could really dial into."

"The Man Who Knew Infinity" hits UK cinemas on Friday and US theatres from April 29.