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Square Root Expression

Directions: Using the digits 1 to 9, at most one time each, fill in the boxes to make the following expression as close to 0 as possible.



What are all the perfect square three digit numbers? Several of these can’t be used since they contain a repeated digit (e.g. 121 uses the digit 1 twice and 144 uses the digit 4 twice)



Using Perfect squares:
Sqrt(256) – sqrt(81) – sqrt(9) = 4

Using non-perfect squares:
Sqrt(145) – sqrt(92) – sqrt(6) = 0.00044178938368

Source: Erick Lee

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  1. Dang it.

    I got:
    √124 – √89 – √3 = -0.030503214

    • You tried. That is what is important!

    • Good job!! It doesn’t matter if you make a mistake! The important thing is that you tried! You did your personal best and that is what matters!!! Just keep trying and you will make a good answer eventually!! Just do your personal best and if you get it wrong than don’t worry about it! it is fine! Keep on trying!

  2. Should it not be √256 – √81 -√49 = 0 ?

  3. The answer should be
    The answer to this equation would be 0

  4. or 11-9-2 when It is simplified

  5. or √121-√64-√9
    The answer would be 0 as well

  6. you are repeating the number 1 , 121 has two and then theres a third “1” in 81

  7. /121-/64-/9=0

  8. Abbey Turrentine


  9. |121|-|81|-|4|

  10. |121|-|81|-|5|

  11. |121|-|82|-|5|

  12. Spencer Turrentine

    121-81-9= 4

  13. I was working on this problem in preparation for having my 8th grade students work on it. I assumed that I should place digits so that the digits under each radical formed a perfect square, but then I realized the directions didn’t explicitly state that. I am interested in hearing how teachers have used this problem in their classroom and the discussions that resulted.

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