Actor Benedict Cumberbatch has made an appearance on children's puppet TV show Sesame Street. The 37-year-old Sherlock actor stopped by the show to help the muppets solve a math problem, reported Ace Showbiz. In the video titled 'Benedict Cumberbatch and the Sign of Four (or is it Three?)', Murray Monster declares himself Murray-arity, a reference to 'Sherlock' villain Moriarty. He asks the British actor to solve a 'brain-bending challenge', which is to determine whether there are more apples or more oranges on the table. The third season of Cumberbatch's Sherlock just wrapped up its run in the US last Sunday, February 2 on PBS. The actor was recently also seen in movies 12 Years a Slave and The Fifth Estate, and lent his voice to the dragon Smaug in The Hobbit: The Desolation of Smaug.