Actress Vidya Balan revisited a school trick to get her role as mathematics genius right in the upcoming film "Shakuntala Devi". "Growing up, math was one of my favourite subjects. I would always look out for interesting ways to learn difficult theories. I still remember my mum would teach us tables in a sing-song fashion," Vidya said.

"So when I arrived on the sets of ‘Shakuntala Devi', I revisited the method. I never thought that those fun ways would come in handy today, in helping me prepare for the movie," she added.