Quirky facts about calculators

• The largest collection of electronic calculators belongs to Gerhard Wenzel (Germany) and consists of 4,113 items as of 7 September 2013 in Solingen, Germany.

• Scott Flansburg of Phoenix, Arizona, USA, correctly added a randomly selected two-digit number (38) to itself 36 times in 15 seconds without the use of a calculator on 27 April 2000 on the set of Guinness World Records in Wembley, UK.

• The most large number roots calculated in one minute is 15 and was achieved by Vikas Sharma (India), in Gurgaon, Haryana, India, on 28 November 2015.The attempt was overseen by a representative from the IMA (International Mental Arithmetic) organisation.