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#6. Brain teaser: can you count the Fs in this sentence?


Quick! Count the num­ber of times that the let­ter F appears in the fol­low­ing sen­tence:


Fin­ished files are the result of years of sci­en­tif­ic study com­bined with the expe­ri­ence of years.”

How many did you find?


Solu­tionMost peo­ple say three. Why? We often don’t cor­rect­ly process the word “OF” for two rea­sons. First, the let­ter F usu­al­ly makes the “f” sound, like in “fox”. How­ev­er, in the word “of”, it makes a “v” sound. Sec­ond, you have prob­a­bly read the word “of” so many times in your life that you process it as one unit, over­look­ing the sec­ond letter/ sound.


Next brain teas­er in Sharp­Brains’ top 25 series:

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45 Responses

  1. Cynthia says:

    There are 6

  2. Shahzad says:

    ha, this test will fail on South Asians where ‘of’ is usu­al­ly pro­nounced as ‘off’ and not ‘ov’

  3. Alvaro says:

    Hel­lo Shahzad, you’re right. Feel free to pro­pose oth­er teasers you have seen may work bet­ter with South Asians!

  4. Liss says:

    I count­ed 7.

  5. KAREN says:

    I FOUND 7

  6. Sheri says:

    Take you time.. there are 6.

  7. miss says:

    i found 6 eas­i­ly

  8. zeda says:

    i found six!

  9. Shenaye says:

    There are 9 f’s

  10. liam says:

    there are defin. 6 f’s in the sen­tence. it’s the f’s in the ‘of’ we humans find it hard to count.

  11. kylie dimock says:

    too many blonds are read­ing this

  12. terrell owens says:

    Hey its ter­rell owens and i count­ed 6

  13. Diana says:

    I’m blond & I count­ed 6. If you count the pre­ced­ing sen­tence there are 9.

  14. Aaron says:

    Yeah I found 6 quite eas­i­ly. How did you guys get 7, I’m curi­ous?

  15. Sasa bacic says:

    There Are 6! Greet­ings from Great Ser­bia

  16. whitne says:

    I won­der if it’s also true that we tend to ignore lit­tle words with­out much mean­ing or emo­tion­al con­tent.

  17. Alvaro says:

    There are 6.

    Whitne: good point. You can try this oth­er exer­cise to see how we tend to ignore lit­tle objects with­out much mean­ing…

    Can you, from mem­o­ry, draw a pen­ny (or any oth­er small coin) and all its ele­ments? Try to do so…and then com­pare with a real one.

  18. Adrian says:

    I count­ed 1 (one).
    I reck­on if we need to count the “fol­low­ing” sen­tence then the sen­tence to be count­ed is [How many did you find?] = 1

  19. Alvaro says:

    Hel­lo Adri­an, very good to think out of the box, but that would be the “fol­low­ing para­graph”, wouldn’t it?

    A very inter­est­ing cog­ni­tive skill is called “the­o­ry of mind”, in which one can ascer­tain the inten­tions of oth­er per­son. Which “sen­tence” do you think we mean?

  20. Adrian says:

    Hi Alvaro, thanx for the reply. I’m a bit rough on gram­mar but I thought any­thing after the colon would be con­sid­ered the ‘same’ sen­tence, not the ‘fol­low­ing’ sen­tence. Maybe I’m think­ing too hard about this one. Cheers.

  21. Alvaro says:

    Helo Adri­an-well, think­ing hard is more than wel­come in this blog 🙂

  22. dcghk says:

    There are 6 as it clear­ly states “ the FOLLOWING sen­tence..”

  23. mariah says:

    i found four f’s. i promise you there are four f’s.

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