1

Add ONLY ONE line (does not have to be a straight horizontal line or in other words, doesn't need to be an axis aligned to the equal sign) to make the equation below true :

EQUATION :

$5$ $+$ $5$ $+$ $5$ $=$ $555$

Notes And Clarification :

  • Crossing the equal sign is not allowed

  • Making a less or more than sign (≤ or ≥) is also not allowed

  • This is not a duplicate of $5$ $+$ $5$ $+$ $5$ $=$ $550$

  • The answer with the most votes will get the green checkmark

Kevin L
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    Are you sure you didn't mean "= 550"? – Alconja Oct 16 '18 at 04:46
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    Nope, this is a new one :D @Alconja – Kevin L Oct 16 '18 at 04:52
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    Does the line need to be perfectly straight like it did in the 550 question? – Arpeggio Oct 16 '18 at 05:36
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    @RyanTheLeach it doesn't need to be "an axis aligned to the equal sign" :D – Kevin L Oct 16 '18 at 07:47
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    @KevinL In comment to this answer you said "I'm still waiting for others to come up with better ones". Can you state in your puzzle what kind of answer you deem better than others and why? – xhienne Oct 16 '18 at 08:02
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    @xhienne I meant that the highest answer (apart from GeorgeMenoutis's answer coz that's a clarification) will get the checkmark in the end :D – Kevin L Oct 16 '18 at 08:04
  • Since this question appears to have many valid answers with no way to tell which one is the best, it has been closed as too broad. – Deusovi Oct 16 '18 at 16:47
  • @Deusovi True, I didn't realize that there will be lots of different answers :D – Kevin L Oct 17 '18 at 02:30
  • @Kevin, out of curiosity, what was the answer you had in mind? – xhienne Oct 17 '18 at 07:49
  • @xhienne My answer is just like Simplifire's answer using congruence XD – Kevin L Oct 17 '18 at 09:11
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    @Kevin Too bad, by subsequently adding "does not have to be a straight horizontal line" to your puzzle, you made it too broad. On the contrary, if you had specified "it must be a straight horizontal line", your puzzle would have had a unique solution (yours). – xhienne Oct 17 '18 at 10:04
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    @xhienne Yea, I guess so but it was still fun making this puzzle :D – Kevin L Oct 17 '18 at 11:11

15 Answers15

23

This equation is true

... in base 14:

$5 + 5 + 5 = 55 / 5$

(in base 14, 5 + 5 + 5 = 11)

xhienne
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18

Using brute force of one heavy stroke line, answer could be :

enter image description here

Or using correction fluid :

enter image description here

15

The one line to be added is:

If we define '+' as string concatenation, the following equation holds:

It needs to be added in front of the equation.

JMP
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M.Herzkamp
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13

Add ONLY ONE line (does not have to be straight)

 

yee
(Line is curvy)

u-ndefined
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12

Given 5+5+5=555 You can make the equation true by adding one line (or symbol).

The angle/ degree symbol.

Where:

5+5+5 = ∠555 (or 555°)

Given that:

the override of ∠555 is 195° (or 15°)).

Therefore:

5+5+5 = ∠555 (or 15° = 555°)

Image:

enter image description here

[Edit] Added further text to include comments that note how my answer can be written in two ways (where one of those two can be drawn with two lines depending on an individual's way of writing).

AnonyTech
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6

This is already true in javascript, if the value 5 is typecasted to string before the equation.
var a = '5'; var result = a + a + a; // produces 555

Naeem Shaikh
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5

I guess this is more probable to add a clarification in the riddle's body rather than be accepted as an answer.

$5 + 5 + 5 \le 555$

George Menoutis
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5

My try!

Working modulo $5$, $$5+5+5\equiv555$$ Actually, this works modulo $k$ whenever $k\mid 540$.

2

one more solution I would like to post,
enter image description here

Naeem Shaikh
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2

Can it be like this ?? I use one line as a border.

Hermes
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    But that won't be a "valid" equation right? I mean you still have unused number outside of the border :D – Kevin L Oct 16 '18 at 08:19
  • @KevinL So? Often you'll see page numbers nearby an equation... do those have to participate in the equation too? – Sneftel Oct 16 '18 at 10:00
  • @Sneftel Interesting find, but unfortunately, it won't be part of the equation :D – Kevin L Oct 16 '18 at 13:07
  • @KevinL That's my point. If it's okay to disregard page numbers, it's okay to disregard stuff outside the box. – Sneftel Oct 16 '18 at 13:39
  • @Sneftel True, well I guess this may count but at the end, the highest voted answer will get the tick :D – Kevin L Oct 16 '18 at 13:39
1

Here's my attempt:

Equation Modified

So you end up with 5 + 55 = 5 + 55

u-ndefined
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TargetDan
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1

  5   
+   55  = 555
Using our base 10 (decimal) system when doing sums. So the first 5 would become 500, the second 50, and the last is the unit.
JorgeeFG
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0

Probably not the answer since i added a dot below the added line.
5 + 5 + 5 != 555

Ano
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Fine, many creative answers are provided. Here are my two cents based on Xhienne's answer-

It is true to say that 5 + 5 + 5 = 55 / 5, in a number system - with base 6

As,

,LHS is 15 (base 6) = 11 ( base 10) and RHS is 55 / 5 (base 6) = 11 (base 6) resulting in 11 on both the sides!

Mea Culpa Nay
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  • Sorry, but your notation is wrong and painful to read. Also, if you introduce different bases, several other solutions arise. For example $5_{10}+5_{10}+5_{10}={15}{10}={11}{14}$ – elias Oct 17 '18 at 06:11
-1

Results in the following equation:

5 + 5 + 5 ≠ 555

AterNyctos
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    No crossing the equal sign :D – Kevin L Oct 16 '18 at 13:30
  • Oops, didn't see that. I guess when I read Notes and Clarification I thought it was an optional read, and as I was so focused on providing "the obvious answer" I didn't even notice. My bad – AterNyctos Oct 17 '18 at 13:03