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Topic: make 100 by using 1, 7, 7, 7, 7
Replies: 41   Last Post: Nov 15, 2007 6:13 PM

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 Robert Israel Posts: 3,262 Registered: 2/1/07
Re: make 100 by using 1, 7, 7, 7, 7
Posted: Nov 13, 2007 12:24 PM

David W. Cantrell <DWCantrell@sigmaxi.net> writes:

> amzoti <amzoti@gmail.com> wrote:
> > On Nov 13, 7:28 am, "Benjamin A. Bartsch"
> > <benjamin.a.bart...@gmail.com> wrote:

> > > dangerousgam...@gmail.com schrieb:
> > >

> > > > So, using only +, -, x, /, and parentheses, and ONLY these numbers:
> > >
> > > > 1, 7, 7, 7, 7
> > >
> > > > how can you make 100? Is there more than one solution?
> > >
> > > ---> (7+1/7)*7*(7/7+1)
> > >
> > > Benjamin

> >
> > That has five 7's and you are only allowed 4.

>
> Right. But I'm not sure that the "solution" 177 - 77 is legitimate either
> since it uses juxtaposition, which is not something which the OP mentioned
> that could be used.
>
> Here's a different solution which does not use juxtaposition:
>
> 7 x 7 + 7 + 7 + 1

Using base 8, are we?
--
Robert Israel israel@math.MyUniversitysInitials.ca
Department of Mathematics http://www.math.ubc.ca/~israel
University of British Columbia Vancouver, BC, Canada

Date Subject Author
11/12/07 dangerousgame95@gmail.com
11/12/07 Thomas Nordhaus
11/12/07 amzoti
11/12/07 quasi
11/12/07 dangerousgame95@gmail.com
11/13/07 magidin@math.berkeley.edu
11/12/07 Thomas Nordhaus
11/12/07 quasi
11/12/07 Joshua Cranmer
11/12/07 Raymond Manzoni
11/13/07 William Elliot
11/13/07 amzoti
11/12/07 David R Tribble
11/12/07 Nat Silver
11/12/07 Raymond Manzoni
11/12/07 Raymond Manzoni
11/13/07 benjamin.a.bartsch@gmail.com
11/13/07 amzoti
11/13/07 David W. Cantrell
11/13/07 magidin@math.berkeley.edu
11/13/07 David W. Cantrell
11/13/07 magidin@math.berkeley.edu
11/13/07 briggs@encompasserve.org
11/13/07 Robert Israel
11/13/07 Dave Seaman
11/13/07 benjamin.a.bartsch@gmail.com
11/13/07 amzoti
11/13/07 David W. Cantrell
11/13/07 Jan Kristian Haugland
11/13/07 Robert Israel
11/13/07 Kira Yamato
11/13/07 Kira Yamato
11/13/07 Robert Israel
11/13/07 amzoti
11/14/07 Thomas Nordhaus
11/15/07 Michael Press
11/14/07 Michael Press
11/15/07 Kira Yamato
11/15/07 Michael Press
11/15/07 Rick Decker
11/13/07 Raymond Manzoni