In an episode of "Silicon Valley", one of the characters goes on a rant about how smart he is and cut his teeth on 'hex tables', and he says, "ask me what F times 9 is. It's fleventy-five!" This is well documented, so I don't think I misheard him.

Now we know that f is 15, so basic maths says that 15*9 is 135 in base-10 or 87 in base-16. I don't think that you can say the answer is d5 because that would be mixing hex and dec, but I'm willing to believe that the writers made that mistake because 87 doesn't sound as impressive. Also, I thought I had heard the word "fleven" before, but now I can't find it except in reference to "Silicon Valley."

What is fleventy-five? Is it d? Are all the hex characters named?

Any insight would be appreciated. Cheers!

  • 4
    $\begingroup$ Seems like a mistake on the show's part. Not sure what "fleven" would mean, but I initially guessed he meant $F5$. As you say, that doesn't work out. $\endgroup$ Commented Jun 15, 2014 at 19:20
  • $\begingroup$ BTW this seems to have been discussed in other places online. For example, there is somewhat related question on quora. $\endgroup$ Commented Sep 3, 2014 at 8:29
  • $\begingroup$ @MartinSleziak A couple of those results are actually my SO question mirrored on different sites. When I searched for it, I found sites promoting the show, as you can see from those results. There are questions about what Fx9 means, but since I have to do hex for my coursework, I'm already familiar with the system. I just didn't know that the term "fleventy-five" was made up, as it sounds like it could be a real thing. But it sounds like there are other results that say that the writer also made up the term 'fleventy-five' $\endgroup$
    – jfa
    Commented Sep 3, 2014 at 17:56
  • $\begingroup$ Total aside but pretty sure that the intent was something like '0F 11 D5' in hex - still clearly wrong but 'fleven' as 'F 11' makes more sense than the previous comment of meaning 'F5' $\endgroup$
    – Abraxas
    Commented Jan 16, 2017 at 7:42

4 Answers 4


T.J Miller says he improvised it in this clip @ 2:50


  • 8
    $\begingroup$ nice user name :) $\endgroup$
    – CPM
    Commented Jun 17, 2015 at 3:30

I think the fact that it doesn't work is even funnier. Clearly Erlich is bluffing and banking on the fact that no one would call him out and check the answer. Fleventy five sounds so believable, you can't help saying to yourself "Oh ok, that's what they must call it".


I cross posted this, and they said in Stack Overflow that this was just a throwaway joke in the show, which I guess I took too seriously.

  • 1
    $\begingroup$ As the question on SO seems to be deleted, I was not able to find the link to the question. So I have added at least a link to the discussion on meta. $\endgroup$ Commented Sep 3, 2014 at 8:26

Pronunciation of hex characters like "fleventy-five" is not a thing that existed before that episode of Silicon Valley.

But in a wonderful case of life imitating art, it now is (or at least could be). See http://www.bzarg.com/p/how-to-pronounce-hexadecimal/ for a full guide!


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