-8
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You may use math signs you wish, but you must use the numbers

7,3,7,3

in an equation so it equals

24

Is it possible? If so, show how.

No-nos:

  • You are not allowed to combine numbers to make bigger numbers (e.g. you can't have 73)
  • You cannot use numbers more than once, you only have 2 7s and 2 3s
  • You have to use all the numbers given to you.

What is a math sign? Examples: +, -, *, /, (, )

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  • $\begingroup$ Do I have to use both numbers exactly twice, or what? $\endgroup$ – No. 7892142 Feb 16 '15 at 12:44
  • $\begingroup$ @No. 7892142 As expected, yes. $\endgroup$ – warspyking Feb 16 '15 at 12:46
  • $\begingroup$ Should you just add characters only to the left of the equals sign? $\endgroup$ – Olive Stemforn Jun 26 '15 at 5:38
  • $\begingroup$ Why are there so many down votes? I mean, I also see this question as a ridiculously simple no-effort quiz, but it's not often too see such a low-scored question recently. (I'm not down voting btw) $\endgroup$ – William Nathanael Jul 16 '17 at 15:07
8
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(3/7+3)*7 =24
=> (3/7 + 21/7) * 7 =24
=> (24/7) * 7 =24
=> 24=24

Took me a while!

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  • $\begingroup$ Not quite... 3/7 = 0.428571428571429 and 3*7 is 21. 21 + 0.428571428571429 is not 24. $\endgroup$ – warspyking Feb 16 '15 at 12:48
  • $\begingroup$ it should be (3/7 + 3)/7 $\endgroup$ – shyos Feb 16 '15 at 12:48
  • $\begingroup$ Silly mistake... apologies! Thanks @shyos $\endgroup$ – The Dragonista Feb 16 '15 at 12:50
6
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Answer

$$((7/7)+3)*(3!) = 4*(3!) = 24 $$

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3
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There's an implied $1$, but I didn't actually write it:

$7 \times 3 + 3 + \int_{\{7\}}dx$

And here's another solution (I think you can argue that $7$ is used twice):

$7 \times 3 - 3 = 24$ in base $7$

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  • $\begingroup$ I love the second one! $\endgroup$ – William Nathanael Jul 16 '17 at 15:03
  • $\begingroup$ I love the second one! $\endgroup$ – William Nathanael Jul 16 '17 at 15:03
2
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Using not all of them:

3*7 + 3 = 24

Using all of them:

$\lceil 7/3 \rceil + 3*7 = 24$

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  • $\begingroup$ "math signs" who said you could use ceil? $\endgroup$ – warspyking Feb 16 '15 at 12:49
  • 2
    $\begingroup$ Who said I couldn't? "Math sign" isn't exactly a rigorous definition. $\endgroup$ – No. 7892142 Feb 16 '15 at 12:50
  • 1
    $\begingroup$ @warspyking "Examples" still does not exclude ceil(). $\endgroup$ – No. 7892142 Feb 16 '15 at 12:53
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    $\begingroup$ Changing the rules to disallow an answer after it's posted sucks, @warspyking; it's incredibly frustrating for someone who's trying to participate in your challenge. Futhermore, the ceiling operation does have what you call a "math sign": $\lceil x \rceil$. Please please review your challenges before you post them and deal with things like this then, rather than snubbing your answerers. $\endgroup$ – Josh Caswell Feb 16 '15 at 20:11
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    $\begingroup$ "Math signs" has no standard definition, @warspyking -- there's nothing to be "not understood". It's up to you to make the rules clear before posting. And, as I showed you, $\lceil\rceil$ is a "math sign". $\endgroup$ – Josh Caswell Feb 16 '15 at 23:58
1
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square root of 7*7 with is 7 * by 3 + 3

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  • $\begingroup$ Hi archie, Welcome to Puzzling SE. Please ensure that your answers make sense to immediate readers, and hide your answers using the spoiler tag >! Alsoif a question already has an accepted answer, be sure your answer adds something good to the puzzle. $\endgroup$ – Spencerkatty Jun 22 '16 at 1:00
1
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I guess square root and factorial are allowed:

$$(\sqrt{7-3} +\sqrt{7-3})! = (2+2)! = 4$$

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0
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((7*7)^{1/2})*3+3
$\sqrt{7*7}*3+3$
$=(7)*3+3$
$=21+3$
$=24$

(equivalent to original answer but w/o using "1/2")
Of course it's unclear if a radical is covered by "math signs" ...

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protected by JonMark Perry Mar 22 at 21:25

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