It’s the Friday Puzzle!


What value should ‘x’ be in the following sequence?

16 06 68 88 x 98

As ever, please do NOT post your answer, but do feel free to say if you have solved it and how long it took. Also, it is ok to leave fake/joke clues (but no real ones!). Solution on Monday!

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

103 comments on “It’s the Friday Puzzle!

  1. Morgan says:

    I like that. It’s a different way of looking at numbers. Very clever. (About a minute.)

  2. Andy SImpson says:

    Bloomin’ heck. Thats the fastest I’ve ever got one! About 90 seconds. Only downside is I really should be working….

  3. Falsedog says:


  4. Nick Titchener says:

    It depends how you look at it.

  5. Eddie says:

    Not bad you just need to know your stuff….

  6. significance says:

    About two minutes. Longer than previous commenters!

  7. taeyoon says:

    I solved it for a min-changing my viewpoint.

  8. M says:

    Don’t see it.
    I’ll return later

  9. G says:

    Can we use letters?

  10. Chris Emerson says:

    Saw it instantly, but there’s no satisfying answer using numbers only :/

    • Goliath says:

      Got the answer but it doesn’t look nice ;(

    • Puddleglum says:

      I agree, not nice, not satisfactory.

    • AMWhy says:

      I misread the question as “should ‘x’ be in the following sequence. That confused me for a moment but when I had the right question, I solved it pretty quick (around a minute) and even instantly thought of how to write the answer BECAUSE of my misreading of the question in the first place…

  11. 4Feit says:

    Less than 1 minute figured out, but I think there is more than one answer

  12. Kinkyclawz says:

    Not sure if I have the correct answer but if I have, it took me 3mins. Slooooow compared to everyone else, huh? šŸ˜€

  13. Suzanne says:


  14. Steve Jones says:

    Have an answer almost instantly, but I couldn’t type it if I wanted to…

  15. rmb says:

    Had no clue after reading the puzzle. Bus solved at a glance after reading the comments.

  16. Kris says:

    I got it in under a minute but that’s not to say I found it easy. Was baffling at first. Good puzzle!

  17. Jules says:

    Same as rmb; was stumped but first few comments had me looking in the right direction…!

  18. Edgar says:

    I think I solved it. The problem is I don’t know how to type it šŸ˜¦

  19. Kate says:

    I have an answer that works, but feel there may be more than one. Under a minute.

  20. Ben Hardwidge says:

    Took me about two minutes – I’d like to say it was very clever, but I actually felt like a bit of an idiot when I found the answer!

  21. Michael says:

    I normally don’t like those kinds of puzzles. But this one was easy to get my head around after about a half minute

    It can even be solved on small phones, as long as they aren’t too much down to earth.

  22. Dana says:

    Took a couple of minutes and then it clicked,look at the numbers.

  23. Gert says:

    Hey, where did you get my phone number?

  24. SlackJawedNut says:

    About 20 seconds

  25. neil j says:

    I feel a bit slow now reading those comments. Love the Friday puzzle, this one took me the longest so far.

    Equally pleasing and irritating when you get it though.

  26. Paul Durrant says:

    About 30 seconds of looking for a pattern before I spotted what was going on.

    While it’s possible to construct a formula to generate that sequence with almost any number at x, I think, having found it, it’s obvious which one the problem setter had in mind.

  27. Matt says:

    Took about a minute, very cute. Although using numbers isn’t quite a perfect fit

  28. Adam says:

    Less than a minute. It’s a bit late to be doing these sorts of puzzles.

  29. Andy says:

    felt like a plum when i finally saw it.

    not entirely sure how to display it though?!

  30. bletherskite says:

    Yay got it, probably wouldn’t have though If I hadn’t read the comments.

  31. Chris says:

    Got it immediately. Having watched a certain episode of Only Connect may have helped though.

  32. Danyc0 says:

    Very nice, fastest one yet for me (75 seconds) šŸ˜€

  33. Atheist Panda says:

    Got it in about 60 seconds, but only because I wrote the sequence down on a sheet of paper in a single column, (hint!)……

  34. Devi says:

    Got it instantly but had the help of the first comment šŸ™‚
    Good one.

  35. Engywuck says:

    Got it! Finally, was L8 by 5 min!

  36. Daryl says:

    quite simple, really. If you take the function

    f(x) = 11 x^6-3476 x^5+417956 x^4-23727440 x^3+639051776 x^2-7194463232 x+24770887680

    and solve for all f(x)=0 you find that x= 16, 06, 68, 88, 40, 98

    • Savant says:

      Daryl may be right but there is an unlimited number of such functions that, on solution, will give an unlimited number of solutions.
      In other words: you can pick an answer and construct a polynomial that will give you your chosen solution. That’s tantamount to cheating!

    • mittfh says:

      Daryl, I think you’re over-thinking the solution šŸ™‚

    • Jarl says:

      Savant and mittfh, read the sarcasm sign

      That said, I still don’t have the solution…

    • Jarl says:

      Ok, got it now

    • Kris says:

      yeah – I did it the same way.

  37. Paul says:

    About 10 seconds, one of those “easy if you’ve seen these type of puzzles before” puzzles.

  38. beanfeast says:

    Struggled with it for a few minutes and couldn’t get it, I even checked the web page, rather than the RSS feed, in case there was a corrected typo. Came back a couple of hours later and saw it straight away. I don’t understand how I missed it the first time round.

  39. Mike Tong says:

    Some unicode characters might help: āˆ  or maybe this Ł

    • LordManley says:

      This is a bit naughty. I had already got it, but I rather fancy your comment is too much of a spoiler.

      Of course, that may only be because I have already ‘got it’.

  40. Harry says:

    Very good, haha.

  41. Milos says:

    Nice one. šŸ™‚
    Took me 2-3min to look into all possibilities and to solve it.

  42. Gerard Engelage says:

    About 30 secs, 25 of them before deciding to write it down

  43. mittfh says:

    About 10 seconds to realise there wasn’t a mathematical solution using the numbers as presented.

    Knowing from previous experience Richard can be quite crafty, I mentally changed my viewpoint and quickly arrived at the most probable solution (although it does break the symmetry of the provided numbers).

    So about half a minute in total – my quickest yet šŸ™‚

  44. Donalbain says:

    I think there are an infinite number of solutions using the pattern that I have spotted.

  45. NeonNero says:

    To those who despair, put that frown upside-down.

    …. What? Did I say too much? šŸ˜‰

    Back on topic, it took me time to solve this. Someone in the comments said something about writing the above numbers down in a single column, and even then, it took a few minutes before it slowly dawned on me what was going on. Simply put, forget about mathematical formulas, you just need to step back and see things from a different angle.

    Also, writing the numbers down in the classic calculator style doesn’t hurt, either.

  46. susqueda says:

    No, the “1” doesn’t work.

  47. Dennis says:

    As I see it, the answer isn’t a “value” at all.

  48. Lazy T says:

    20 seconds gets me eight quid! I wish that was my usual rate…

  49. Mr. D says:

    Hmm. I’ve got an answer, not entirely happy with it, because it doesn’t quite look right, but it fits. I’ll have to wait for Monday.

    Took me about 5 mins, couldn’t see it straight away, so I did what I often do with these puzzles; walked away and when I came back I got it in about 30 seconds.

  50. Waldo says:

    I usually skip the math ones, but I stuck with this one long enough to see the trick. About a minute. Good one.

  51. Doug says:

    Got it in about 10 minutes of making my head hurt.

  52. Gordon says:

    I don’t know. I think I’m just too late.

  53. Manbat says:

    just under 90 seconds.

  54. EC says:

    Less than 10 seconds. It’s the sort of spin that some people notice immediately. On the other hand, why is the time important? As Professor I.M. Gelfand used to say, “you have to be fast only to catch fleas”.

  55. Sari1967 says:

    Think I got it not too hard but made me think.

  56. Neal says:

    Ha Ha, didn’t get it at all until I gave up and looked at the comments.

  57. Jenny says:

    Finding it funny how so many people can’t resist showing off that they have the right answer by giving overly-obvious clues. Interesting. Glad I solved it before looking at any comments (about 10s).

  58. Matt says:

    I got the principle in about 10 seconds, then struggled over the first character – in the end I had to write it down to “work out” the first character

  59. Rufus says:

    Nice puzzle, I solved it and it gave me some satisfaction.

    I’m annoyed by the way that so many people write down how long it took them to solve it. Surely the joy of these puzzles and problems is in working them out, not in solving them quickly or more quickly than others.

  60. David Batty says:

    Rufus: Richard invited people to let him know if they have solved it and how long it took them to complete the puzzle, now he also knows how many people didnt read the instructions.

    • Rufus says:

      yeah, I saw that after I posted. Think it’s a bad idea. Is the motivation to do these puzzles in the ego-boost of solving them quickly or in the pleasure of solving them? Maybe people could comment on whether they enjoyed the puzzle and why.

      I enjoyed the challenge of this one, and the neatness of the answer.

  61. Cozdas says:

    Less than 2 minutes. Good one indeed.

  62. RobHes says:

    You guys are all crazy – it’s just a bunch of random numbers. Meaningless. I’m not falling for th

    Oh look! Look at that! Nice!
    In your face, world! Who’s the daddy?

  63. Asgeir Rekkavik says:

    Perhaps two minutes. Clever puzzle. Very happy to have solved it.

  64. Rob says:

    Came to me in a couple of minutes. Feel quite clever now.

  65. The Pick Man says:

    I came to the answer quickly when I remembered that the question was first set for Dorothy by the Wizard of Oz

  66. D says:

    About 2 minutes. Nice! šŸ˜€

  67. M Roig says:

    I would imagine Australians will see this straight away.

  68. Vicki says:

    Wow! Very impressed with myself – saw it after about 15 seconds. I hardly ever solve them usually.especially when they’re number based.

  69. Julia says:

    Luckily I am sick. Scribbled down the numbers before going back to bed, then looked at the note. Easy.

  70. JamesMaullin says:

    Took me about a min but was very simple – reminds me of whats it called… the thatcher effect? I think… Something along those lines

  71. jamie says:

    Fun one! After following the Friday Puzzles for a bit, you know that you need to think outside the box to solve some of them. After reading the first couple of comments, I got it right away.,

  72. niki says:


  73. says:


  74. Vern says:

    A terrific time Saturday night. We surprised my parents and they were thriled when they got there..Thank you! I used to be advised by the photo booth person that pictures would be online. Where are they?

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