Question

Using the digit 7 five time, place the basic arithmetic signs in between the digits to obtain a total of 540

Answer 1

nice question.....

Answer 2

I know, it's been driving me nuts

Answer 3

can you join two 7s together to form 77?

Answer 4

Nah, you gotta put the signs in between each one

Answer 5

You're going crazy, aren't you?

Answer 6

this question is right r u sure?

Answer 7

because if it is not then bad things will happen

Answer 8

Yeth, I'm pretty sure it's the question

Answer 9

And now everyone's thinking...

Answer 10

It would be fast to do with computer code, any one good with programming ?

Answer 11

certainly question of the week

Answer 12

yes certainly

Answer 13

if it doesn't get solved here put it in the meta-math section for future reference

Answer 14

I've really been trying this for a while and I think it's messed up
anyone else think it's impossible?

Answer 15

as in, it's total overload here

Answer 16

i'm not sure if this fits the rules but
77 x 7 + (7 / 7) gives 540

Answer 17

+ - / and * only, right?
no squaring or anything?

Answer 18

concatenation isn't arithmetic right?


nice work jimmyrep btw

Answer 19

jimmyrep, if no one can find a solution without the placing two 7s together, I'll use your solution

Answer 20

ok

Answer 21

i don't think you can do it without joining two 7s together, jimmy rep has the right answer.

Answer 22

77 is probably not allowed

Answer 23

jimmy rep yehh 77 not allowd

Answer 24

It's probably not, but if it isn't I think it's impossible. I've been over this for over two hours, can't do anything to solve it. Yes, two hours, that's how obsessed I am with this question.

Answer 25

these types of question are obsessive!

Answer 26

Yep

Answer 27

you can't do it because 540 is not divisible by 7.

Answer 28

I KNEW IT! All that time wasted, I COULD'VE BEEN PLAYING TETRIS!

Answer 29

lol

Answer 30

Sweet baby turtles, I can't believe I missed that fact

Answer 31

that doesn't make a difference, you can make four 5's into 26 even though 26 is not divisible by 5
5*5+(5/5)

Answer 32

Oh I see.....

Answer 33

in jimmy's example, he used 7/7 to add 1...

Answer 34

Oh, yeah, then my time HASN't been a complete waste

Answer 35

Good observation...

Answer 36

are parentheses allowed?

Answer 37

I would think so... it's just multiplication

Answer 38

Yeah

Answer 39

i was thinking maybe there was an order of operations trick to solving it or something... grasping at straws :-)

Answer 40

You don't need them though, order of operations takes care of the problem above.

Answer 41

yes - i didn't need the parenthesis

Answer 42

It all depends on if digits can be stacked without operations (is 77 valid?) - in which case 7*77+7/7 works as jimmyrep mentioned

Answer 43

question y u no make sense? ლ(ಠ益ಠლ)

Answer 44

I feel like concatenation is needed here though. I'm not sure there's another way to grow the number fast enough while reserving 7/7 to make the difference of 1 you need to get to 540 itself.

Answer 45

this is certainly a crap question because 540 is not divisible by 7 and i advise ppl to stop wastin time on it

Answer 46

I already pointed out that the fact that 540 is not divisible by 7 makes no difference, read above

Answer 47

the problem is sitting in meta-math now, so it can be viewed in the future by someone who can figure this out, or prove it to be impossible.

Answer 48

Sooooooo, you can't get a straight answer right?

Answer 49

not here, not now...

Answer 50

this is correct answer

Answer 51

Bummer huh

Answer 52

Oh, well, guys I don't want to completely waste all your time

Answer 53

So, if everyone please get together with the plan and just randomly give everyone you can medals!

Answer 54

Like I say, check the meta-math section in the future, someone will probably either find the answer or prove it impossible... eventually.

Answer 55

Thanks, to everyone, for all the help

Answer 56

what an awesome way to waste time

Answer 57

:)

Answer 58

Well, medals or wasted time right? Might as well

Answer 59

but to prove it impossible without a computers help is going to be interesting

Answer 60

moneybird has a knack for this kind of thing, but he's not around.

Answer 61

Yep, but it's gonna take a looot of time and luck

Answer 62

Yeah, something about koalas that makes him as smart as he is

Answer 63

jejeje...

Answer 64

yo

Answer 65

why r ppl still on this question,
u u ppl stil solving it?

Answer 66

I'm thinking it is impossible:
adding 7/7=1 is the only way I can see to get to a number that is not divisible by 7, which only leaves three 7's left over, and the most we can make that into is
7*7*7=343
taking 540-(7/7)=539
and
539/7=77
hence it seems jimmyrep's answer is the only one possible, but I don't think this is a true proof that it is impossible.

Answer 67

I tried a bunch of different ways, and I can't find an answer. Now I have a Chem Final in 45min., and this problem is all I'll be thinking of!

Answer 68

JIMMY IS CORRECT :P