Author
|
Topic: Simple but fun math problem
|
Percy
Member Posts: 22499 From: New Hampshire Joined: 12-23-2000 Member Rating: 4.9
|
|
Message 1 of 21 (388680)
03-07-2007 8:15 AM
|
|
|
I heard this on a podcast, I won't say which one in order to discourage people from looking up the answer. Place three digits, 2, 7 and one other, in an expression that equals 8. You can use +, -, *, / and exponentiation. Decimal points and parentheses may be used freely, but each digit may only appear once in the expression. Do this nine times where the remaining digit is 1 through 9. When you're done you'll have 9 expressions, each consisting of only three digits (2, 7 and the remaining digit of 1 through 9) and all equal to 8. For example, when the third digit is 1, the expression is:
7 + 2 - 1 = 8 Now find the remaining 8 expressions. --Percy
|
Neutralmind
Member (Idle past 6151 days) Posts: 183 From: Finland Joined: 06-08-2006
|
|
Message 2 of 21 (388683)
03-07-2007 8:35 AM
|
|
|
I can't even think of one... I can't understand how this is simple for anyone. Though, I barely passed short mathematics in upper secondary school
|
BMG
Member (Idle past 236 days) Posts: 357 From: Southwestern U.S. Joined: 03-16-2006
|
|
Message 3 of 21 (388687)
03-07-2007 9:25 AM
|
Reply to: Message 1 by Percy 03-07-2007 8:15 AM
|
|
Here's two simple ones... {2*7} - 6 = 8 {7-2} + 3 = 8
This message is a reply to: | | Message 1 by Percy, posted 03-07-2007 8:15 AM | | Percy has not replied |
|
Wounded King
Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: 04-09-2003
|
|
Message 4 of 21 (388688)
03-07-2007 9:32 AM
|
Reply to: Message 1 by Percy 03-07-2007 8:15 AM
|
|
I think I have them all SPOILERSPACE (highlight the blank area to see it) 7+(1^2)=8 (2/2)+7=8 (7-3)*2=8 2^(7-4)=8 This next one is based on my tenuous understanding of Percy's 'Dot' hint, so it might be mathematical nonsense... (7-...-5)^2=8 (7*2)-6=8 72/9=8
END SPOILERSPACE Hi Percy, if you could tell me exactly what the HTML code is for the colour of the message background I can hide my spoiling better. At the moment I'm using #214666 but I'm not sure how close it is. *ABE* I'll keep working on those missing ones*ABE* TTFN, WK Edited by Wounded King, : No reason given. Edited by Wounded King, : No reason given. Edited by Wounded King, : No reason given. Edited by Wounded King, : No reason given. Edited by Wounded King, : No reason given.
This message is a reply to: | | Message 1 by Percy, posted 03-07-2007 8:15 AM | | Percy has replied |
Replies to this message: | | Message 5 by Percy, posted 03-07-2007 9:43 AM | | Wounded King has replied | | Message 14 by kuresu, posted 03-07-2007 12:26 PM | | Wounded King has not replied |
|
Percy
Member Posts: 22499 From: New Hampshire Joined: 12-23-2000 Member Rating: 4.9
|
One easy way to hide things is to use this approach:
This text will be hidden. People can click on "peek" to see the hidden text. It looks like you've provided an additional solution for 1, three solutions for 3 (one of which is incorrect), two solutions for 9, and no solutions for 4, 5, 7 or 8. --Percy
This message is a reply to: | | Message 4 by Wounded King, posted 03-07-2007 9:32 AM | | Wounded King has replied |
|
Wounded King
Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: 04-09-2003
|
|
Message 6 of 21 (388691)
03-07-2007 9:48 AM
|
Reply to: Message 5 by Percy 03-07-2007 9:43 AM
|
|
I didn't appreciate that you wanted 1 solution for each of 1-9. TTFN, WK
This message is a reply to: | | Message 5 by Percy, posted 03-07-2007 9:43 AM | | Percy has not replied |
|
Neutralmind
Member (Idle past 6151 days) Posts: 183 From: Finland Joined: 06-08-2006
|
|
Message 7 of 21 (388692)
03-07-2007 10:00 AM
|
|
|
Oh, I thought you could only change the last -/+ mark. No wonder it felt impossible.
|
Percy
Member Posts: 22499 From: New Hampshire Joined: 12-23-2000 Member Rating: 4.9
|
|
Message 8 of 21 (388695)
03-07-2007 10:23 AM
|
Reply to: Message 5 by Percy 03-07-2007 9:43 AM
|
|
Just so people realize what WoundedKing is doing, he's filling in the answers in the blank space as he figures them out. Edited by Percy, : Clicked too soon.
This message is a reply to: | | Message 5 by Percy, posted 03-07-2007 9:43 AM | | Percy has not replied |
|
Jazzns
Member (Idle past 3939 days) Posts: 2657 From: A Better America Joined: 07-23-2004
|
|
Message 9 of 21 (388696)
03-07-2007 10:39 AM
|
|
|
5 & 7
are stumping me...
Of course, biblical creationists are committed to belief in God's written Word, the Bible, which forbids bearing false witness; --AIG (lest they forget)
Replies to this message: | | Message 10 by Percy, posted 03-07-2007 11:15 AM | | Jazzns has not replied |
|
Percy
Member Posts: 22499 From: New Hampshire Joined: 12-23-2000 Member Rating: 4.9
|
|
Message 10 of 21 (388704)
03-07-2007 11:15 AM
|
Reply to: Message 9 by Jazzns 03-07-2007 10:39 AM
|
|
Re: 5 & 7
Dots are good, and be devisive. --Percy Edited by Percy, : Wrong hint.
This message is a reply to: | | Message 9 by Jazzns, posted 03-07-2007 10:39 AM | | Jazzns has not replied |
|
Discreet Label
Member (Idle past 5091 days) Posts: 272 Joined: 11-17-2005
|
|
Message 11 of 21 (388709)
03-07-2007 11:43 AM
|
Reply to: Message 1 by Percy 03-07-2007 8:15 AM
|
|
Not perfect but close
271 - 7+2-1 272 - 7+2/2 273 - 7+3-2 274 - 2^(7-4) 275 - .5*2+7 276 - 2*7-6 277 - 278 - .2+7+.8 279 - 72/9
8 of 9
This message is a reply to: | | Message 1 by Percy, posted 03-07-2007 8:15 AM | | Percy has not replied |
|
Zawi
Member (Idle past 3657 days) Posts: 126 From: UK Joined: 12-02-2004
|
|
Message 12 of 21 (388715)
03-07-2007 12:18 PM
|
|
|
Just realised that this question can be done with 0 as well. Highlight the text below for the cheeky answer: ________________ 7 + 2^0 = 8 ________________ Edited by Zawinul, : No reason given. Edited by Zawinul, : No reason given.
|
Modulous
Member Posts: 7801 From: Manchester, UK Joined: 05-01-2005
|
|
Message 13 of 21 (388717)
03-07-2007 12:21 PM
|
Reply to: Message 1 by Percy 03-07-2007 8:15 AM
|
|
7 + (2/2) = 8 7+3-2= 8 2(7-4)=8 (.5 * 2) + 7 =8 (2 * 7) - 6 =8 2 7 7 =8 7.8 + .2 = 8 (7+9) / 2=8
Still thinking about 5 and 7... edit: just 7 now...peek to see. Edited by Modulous, : No reason given.
This message is a reply to: | | Message 1 by Percy, posted 03-07-2007 8:15 AM | | Percy has not replied |
Replies to this message: | | Message 16 by Straggler, posted 03-07-2007 12:38 PM | | Modulous has not replied |
|
kuresu
Member (Idle past 2540 days) Posts: 2544 From: boulder, colorado Joined: 03-24-2006
|
hey WK--it takes a good boacklight and good light conditions to see them. First I saw them, I was in laptop mode, so virtually no backlight, and couldn't see them. now I can. but just so slightly.
This message is a reply to: | | Message 4 by Wounded King, posted 03-07-2007 9:32 AM | | Wounded King has not replied |
|
Zawi
Member (Idle past 3657 days) Posts: 126 From: UK Joined: 12-02-2004
|
|
Message 15 of 21 (388720)
03-07-2007 12:36 PM
|
Reply to: Message 1 by Percy 03-07-2007 8:15 AM
|
|
I've got 0 through 9, except for 5 and 7. Does this count for 8?: 7.2 + .8 = 8
This message is a reply to: | | Message 1 by Percy, posted 03-07-2007 8:15 AM | | Percy has replied |
Replies to this message: | | Message 17 by Percy, posted 03-07-2007 12:48 PM | | Zawi has not replied |
|