In 1977, at Southern Methodist University, she was asked to give the 23rd root of a 201-digit number; she answered in 50 seconds. Her answer 546,372,891 was confirmed by calculations done at the US Bureau of Standards by the UNIVAC 1101 computer, for which a special program had to be written to perform such a large calculation.
On 18 June 1980, she demonstrated the multiplication of two 13-digit numbers 7,686,369,774,870 × 2,465,099,745,779—picked at random by the Computer Department of Imperial College, London. She correctly answered 18,947,668,177,995,426,462,773,730 in 28 seconds. This event is mentioned in the 1982 Guinness Book of Records [x]
Here is a video about her with her answering some equations: [x]