#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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  1. Cynthia on September 27, 2007 at 10:25

    There are 6

  2. Shahzad on October 18, 2007 at 8:49

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

  3. Alvaro on October 18, 2007 at 6:59

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

  4. Liss on November 29, 2007 at 6:49

    I count­ed 7.

  5. KAREN on December 6, 2007 at 8:26

    I FOUND 7

  6. Sheri on December 6, 2007 at 6:30

    Take you time.. there are 6.

  7. me on December 11, 2007 at 10:05

    6 f’s

  8. miss on January 11, 2008 at 10:26

    i found 6 easily

  9. zeda on January 16, 2008 at 9:52

    i found six!

  10. Shenaye on January 25, 2008 at 1:22

    There are 9 f’s

  11. liam on January 26, 2008 at 6:01

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

  12. kylie dimock on February 18, 2008 at 3:08

    too many blonds are read­ing this

  13. terrell owens on February 28, 2008 at 8:30

    Hey its ter­rell owens and i count­ed 6

  14. Diana on March 14, 2008 at 5:11

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

  15. mojtaba on March 17, 2008 at 8:01


  16. Aaron on March 23, 2008 at 10:14

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

  17. Sasa bacic on March 24, 2008 at 3:34

    There Are 6! Greet­ings from Great Serbia

  18. whitne on April 1, 2008 at 7:21

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

  19. Alvaro on April 1, 2008 at 11:00

    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.

  20. Adrian on April 7, 2008 at 8:55

    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

  21. Alvaro on April 10, 2008 at 10:37

    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?

  22. Adrian on April 16, 2008 at 8:15

    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.

  23. Alvaro on April 17, 2008 at 1:22

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

  24. dcghk on May 7, 2008 at 11:14

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

  25. mariah on July 14, 2008 at 10:17

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

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