Over the years, Channel 4 viewers have tuned in as Countdown maths gurus Carol Vorderman and Rachel Riley give us head-scratching maths problems. But some of the Countdown rounds have been solved - somewhat unbelievably - within moments.

       In fact, some of the trickiest and toughest rounds posed to those competing have ended in a record time of under 30 seconds.

       Below are some of the toughest we've seen over the years - and the players responsible for getting to a solution.

       Maths wizard

       James had 30 seconds use the numbers 25, 50, 75, 100, 3, and 6 to calculate how to get as close to 952 as possible.

       Here's how he did it:

       100 + 6 = 106

       106 x 3 = 318

       318 x 75 = 23,850

       23,850-50 =23,800

       23,800/25

       =

       952

       Terrific George

       In October 2014, George was tasked with using 1, 2, 25 and 100, as well as 75 and 50, to get to 940.

       George managed it by doing:

       75 x 25 = 1875

       He then added one for 1876, before multiplying by 50 for 93800, and divided by 100 to give 938, before adding 2.

       "Well done!" exclaimed Rachel Riley.

       "Terrific George," said Nick Hewer.

       'Where did we find this guy?'

       To get 813, Carol tasked two contestants with using 1, 10, 25, 50, 75 and 100.

       John said he had 813, using:

       75 - 10 = 65

       65 x 25 = 1625

       1625 + 1 = 1626

       1626 x 50 = 81300

       81300 divided by 100 = 813

       "Where did we find this guy?" asked Richard Whiteley.