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111 votes

3:3! It's a football score!

Does this count?
Yly's user avatar
  • 759
108 votes
Accepted

3:3! It's a football score!

If you are allowed to use decimals, then
Cameron White's user avatar
87 votes
Accepted

The mother of all age-of-the-captain riddles

phenomist's user avatar
  • 13.6k
78 votes
Accepted

How many consecutive positive integers can you make using exactly four instances of the digit '4'?

Answer: How?
f'''s user avatar
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74 votes

Use the numbers 1-9 to equal 1150

Here's an answer which
Rosie F's user avatar
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73 votes

4 Attempts to Guess a Number Between 1-15

Yes. Guess 1st set (1,3,5,7,9,11,13,15) -> If the number is in the set, write down 1 Guess 2nd set (2,3,6,7,10,11,14,15) -> If the number is in the set, write down 2 Guess 3rd set (4,5,6,7,12,13,14,15)...
Chris Cudmore's user avatar
71 votes

3:3! It's a football score!

Since the puzzle oddly and specifically mentions the symbol for the square root, I used this: but rotated and reflected it giving:
Dan Russell's user avatar
67 votes

3:3! It's a football score!

Another answer could be
dcfyj's user avatar
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67 votes
Accepted

The Cucumber Paradox

I'm gonna say: Explanation:
votbear's user avatar
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63 votes
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Correct way to add 22 to 4 to get given value

If you consider the numbers as Then
KoA's user avatar
  • 2,440
62 votes
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Make e using 1, 2, 3, 4, 5, 6, 7, 8, 9

Parcly Taxel's user avatar
  • 7,698
60 votes
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Number 88 from the digits 2, 0, 1 and 7?

What about this where
hexomino's user avatar
  • 136k
56 votes
Accepted

Create all numbers from 0-100 only using all of 1,2,3,4 and 5

Also, you can use any operation. Ok then. $\begin{array}{c|c} 0 & \log_{\frac1 2} \left( \log_{4!!-3} 5 \right) \\ 1 & \log_{\frac1 2} \left( \log_{4!!-3} \sqrt 5 \right) \\ 2 & \log_{\...
minseong's user avatar
  • 753
55 votes

4 Attempts to Guess a Number Between 1-15

A simple way is to pick the number $X$ which is half-way through the range and ask Is it less than $X$? From the answer you can discard either the lower half or the upper half of the range. ...
Weather Vane's user avatar
  • 14.5k
54 votes

9-5=5? Matchstick problem

Another solution:
Scott Miller's user avatar
53 votes

Number 88 from the digits 2, 0, 1 and 7?

No rules? Looks like 88 to me if I squint.
Andrew Morton's user avatar
49 votes

A truly amazing way of making the number 2016

JMP's user avatar
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48 votes
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A truly amazing way of making the number 2016

And three more à la Perry
Pietro Majer's user avatar
48 votes
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Doubling/tripling puzzle: make 1 from 1536 in as few steps as possible

As Jo has already shown, this can be accomplished in To help visualize this problem, we can imagine: Proving minimality:
ManyPinkHats's user avatar
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48 votes

Combine 1,3,3,7 to get 10

As quite standard in this kind of hard number puzzle, we can: Another example of this form being the only solution is: Use 1, 2, 3, 8 to make 28 with the unique (up to commutation) solution being:
justhalf's user avatar
  • 6,034
47 votes
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9-5=5? Matchstick problem

Here's one way: For the image-impaired:
tmpearce's user avatar
  • 4,135
47 votes
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Why are all numbers from 1 to 2N covered by weights with powers of 3?

It helps to think about the scale not in terms of balancing two objects, but in terms of creating a weight difference between the two sides. (If you want to balance out an object, you simply put ...
Deusovi's user avatar
  • 146k
45 votes
Accepted

Can you explain these equations?

The equations are I don't really feel like calculating all of them, but for the first and second one: The edit history hint helped a lot with this one. Edit: For completeness here are all three:
Rauwyn's user avatar
  • 496
43 votes

How to get 5 from 0,0,0 and 1?

First off, latest edit - just for fun, how to get 5 from just 0 and 1: Before rule change posted: With the changed rules: And while we're at it, here's $0$ to $28$: And here's how to get 5 from ...
Paul Evans's user avatar
  • 9,431
43 votes

The computer can't do anything I couldn't do with pen and paper

Not sure if this counts as "pencil-and-paper" but certainly counts as "no computer..." $$ 3^{100} = 10^{100 \log 3} $$ We can compute this logarithm using a slide rule. The D and L ...
2012rcampion's user avatar
  • 18.9k
42 votes
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Is this sequence that hard?

Probably way over thinking this: There is a hint that: Reason:
p.s.w.g's user avatar
  • 861
42 votes

How do you get 23 using the numbers 1, 2, 3 and 5?

As stated the problem is not possible. Here's an online solver to show that. Lateral thinking options could fix it (like @Apep (reinterpretation of the list), @jlars62(decimal point (very clever)), ...
Dr Xorile's user avatar
  • 23.5k
42 votes
Accepted

A strange operator on my new calculator

I think the operation replacing + is Examples Finally the last result produces an error because In fact
hexomino's user avatar
  • 136k
40 votes

3:3! It's a football score!

The simplest one is:
KeyboardWielder's user avatar
40 votes

Create all numbers from 0-100 only using all of 1,2,3,4 and 5

$\begin{align} 0 & = (1 + 2 - 3) \times (4 + 5) \\ 1 & = 1 + (2+3-5) \times 4 \\ 2 & = 2 + (1+3-4) \times 5 \\ 3 & = 1 -2+3-4+5 \\ 4 & = 1 \times (2+3-5) + 4 \\ 5 & = 1-2-3+4+...
Marius's user avatar
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