Called, quite simply, 'Family discussion in Belfast', this video of Amber May posing a basic maths problem to her 19 year-old sister Laurel has become something of an internet sensation.
Why? Partly because Laurel is totally flummoxed by the simple question ‘how long does it take to travel 80 miles at 80mph?’ And partly because the pair's mother keeps interjecting - and swearing - with disbelief at her daughter's inability to answer it correctly.
Imagine 'The Royle Family' set in Northern Ireland - with added slapstick - and you're part way there...