2024 AMC 8 Problems/Problem 4

Problem

When Yunji added all the integers from to , she mistakenly left out a number. Her incorrect sum turned out to be a square number. What number did Yunji leave out?

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   ./'       "--`\//
 ./              o \          .-----.
/./\  )______   \__ \        ( help! )

./ / /\ \ | \ \ \ \ /`-----'

  / /  \ \  | |\ \  \7--- ooo ooo ooo ooo ooo ooo

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Roses are red

violets are blue

Grass is green

Chair

Solution 3

Recall from AMC12A 2022 Problem 16, that . Hence removing works and our answer is .

-iamcalifornia'sresidentidiot

Solution 4

using the theory of relativity, 1+5 is 4 so therefore Mark Zuckerburg is a lizard person and the earth is actually flat, which proves the pythagorean theorom

-by random_uwu_gamer_girl

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Video Solution 1 (easy to digest) by Power Solve

https://youtu.be/HE7JjZQ6xCk?si=sTC7YNSmfEOMe4Sn&t=179

Video Solution by Math-X (First fully understand the problem!!!)

https://youtu.be/BaE00H2SHQM?si=9ZUxEGmGam7il9xr&t=907

~Math-X

Video Solution by NiuniuMaths (Easy to understand!)

https://www.youtube.com/watch?v=Ylw-kJkSpq8

~NiuniuMaths

Video Solution 2 by SpreadTheMathLove

https://www.youtube.com/watch?v=L83DxusGkSY

Video Solution by CosineMethod [🔥Fast and Easy🔥]

https://www.youtube.com/watch?v=9v5q5DxeriM

Video Solution by Intersigation

https://youtu.be/ktzijuZtDas&t=232

See Also

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.