Simple but interesting math puzzle

Question

Four numbers are available: $1$, $3$, $4$ and $6$. Every number must be used once and only once with (some of) the operations $+$, $-$, $\times$, $\div$ to form the number $24$.

It's from the book "Art of Exploitation", 2nd edition. Give it a try!

no it is not okay, you can only use +, -, * and / once at time. — , Mar 08 '16 at 13:09

score 20 · Answer 1 · edited Mar 08 '16 at 18:09

20

An answer to this problem is:

$6 \div (1 - \frac34)$

edited Mar 08 '16 at 18:09

GentlePurpleRain

25,965
6
93
155

answered Mar 08 '16 at 12:45

user19986

201
1
3

2

Great first answer and welcome to puzzling.stackexchange. It is customary to hide answers by using the spoiler tag >! to give others a chance to solve it on their own. – Hugh Meyers Mar 08 '16 at 12:53

score 1 · Answer 2 · answered Mar 08 '16 at 19:08

1

A possible interpretation of the rules:

$1+3+4+6=24_{5}$

answered Mar 08 '16 at 19:08

8BitTRex

11
1

score -2 · Answer 3 · edited Mar 08 '16 at 18:10

-2

Another possible answer could be...

$(14-6) \times 3 = 24$

edited Mar 08 '16 at 18:10

GentlePurpleRain

25,965
6
93
155

answered Mar 08 '16 at 17:20

user19997

17

3

the problems says the NUMBERS 1,3,4, and 6, not the DIGITS 1,3,4, and 6 – Kevin Mar 08 '16 at 17:31

score -3 · Answer 4 · answered Mar 08 '16 at 12:57

-3

Bit of an off the wall answer

(6-4)(3+1) forms 24 if you calculate the values within the brackets, and leave the results as they are

Not mathematically correct at all I know, it's an answer that loosely fits the wording of the puzzle

answered Mar 08 '16 at 12:57

Lynch

190
4

score -4 · Answer 5 · edited Mar 08 '16 at 18:10

-4

Answer could also b:

$6 \times 4 \times 1^3$

edited Mar 08 '16 at 18:10

GentlePurpleRain

25,965
6
93
155

answered Mar 08 '16 at 12:50

Ben

2,617
12
35

4

Exponents weren't allowed in the puzzle – Lynch Mar 08 '16 at 12:51
where does it say that? I would write a little 3 without the '^' but don't know how to here.... – Ben Mar 08 '16 at 12:55
1

The question states the operators you can use are +, -, * and / – Lynch Mar 08 '16 at 12:55
I understand - but would it not be correct to write 1(little 3) and I would avoid the exponent operator? I have totally no idea if that makes sense (I'm not great in the math department) please explain... – Ben Mar 08 '16 at 12:58
1

Doesn't matter if you write multiplication as 3 x 4, or 3 * 4, they both equal 12. The operation is the same, and that's what's limited in the puzzle – Lynch Mar 08 '16 at 12:59
@Lynch in python you can do power function by doing ** and as * is allowed, and there is no specify notation – user902383 Mar 08 '16 at 13:05
In PHP, and other languages, you can use ++ to increment a number. But neither ** nor ++ were specified as operators. I could be wrong of course, we'll have to wait for OP to confirm – Lynch Mar 08 '16 at 13:06
3

@user902383 I would argue even though both operators ** and * use the same characters, they are very different operators, and it is not at all clear you may combine the characters to a new operator. – Block Mar 08 '16 at 13:16

Simple but interesting math puzzle

5 Answers5