Among her distinctions was her ability to, given a date in the last century, mentally ascertain the day.

The ‘human computer’, ‘mental calculator’, math whiz Shakuntala Devi passed away here early on Sunday aged 80.

Ms. Devi, who was suffering from respiratory problems and later developed heart and kidney complications, had been in a Bangalore hospital for two weeks.

Ms. Devi held a Guinness World Record for her lightning-speed calculations. Among her distinctions was her ability to, given a date in the last century, mentally ascertain the day.

In 1977, she calculated the 23rd root of a 201-digit number in just 50 seconds. In 1980, she multiplied two 13-digit numbers given to her randomly by the Computer Department of Imperial College, London.

“It is sad that her techniques to simplify math were not used by educational institutions,” said D.C. Shivdev, a trustee of the Shakuntala Devi Educational Foundation Public Trust.

“She strove to simplify math for students and help them get over their math phobia. It is a pity that her techniques died with her.”

She authored several books including Fun with Numbers, Puzzles to Puzzle You, and Awaken the Genius in Your Child.

Child prodigy

An indisputable child prodigy, Ms. Devi began to give public demonstrations of her math skills at the age of just six. But it was even earlier, when she was three, that her father — a trapeze artist and lion tamer — first discovered her genius.

Her father, who had rebelled against his orthodox Brahmin family’s wish that he join a circus rather than become a temple priest, noticed his daughter’s uncanny ability to memorise while teaching her a card trick.

Impressed by her gift, he then travelled with Ms. Devi on road shows where she performed her mathematical feats. Ms. Devi, who had no formal education, had once described her ability as a ‘gift’.