Re: make 100 by using 1, 7, 7, 7, 7
- From: Kira Yamato <kirakun@xxxxxxxxxxxxx>
- Date: Tue, 13 Nov 2007 13:59:31 -0500
On 2007-11-13 13:51:55 -0500, Kira Yamato <kirakun@xxxxxxxxxxxxx> said:
On 2007-11-13 13:22:13 -0500, Robert Israel <israel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> said:
"Benjamin A. Bartsch" <benjamin.a.bartsch@xxxxxxxxx> writes:
dangerousgam...@xxxxxxxxx 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?
--> (1/7+7)*(7+7)
Benjamin
Yes, and that's the only solution (up to commutativity).
I'm very curious how you concluded this. Was it by a program that tests through all possible combinations?
I tried to write a program too, but I stop when I couldn't quickly find a way to list out all possible trees with 7 leaves.
Sorry, I meant 5 leaves. My idea was that each expression can be represented as a tree where each internal node is one of four operators +,-,*,/ and the leaves are one of the number 1,7,7,7,7.
--
-kira
.
- References:
- make 100 by using 1, 7, 7, 7, 7
- From: dangerousgame95
- Re: make 100 by using 1, 7, 7, 7, 7
- From: Benjamin A. Bartsch
- Re: make 100 by using 1, 7, 7, 7, 7
- From: Robert Israel
- Re: make 100 by using 1, 7, 7, 7, 7
- From: Kira Yamato
- make 100 by using 1, 7, 7, 7, 7
- Prev by Date: Re: make 100 by using 1, 7, 7, 7, 7
- Next by Date: Re: make 100 by using 1, 7, 7, 7, 7
- Previous by thread: Re: make 100 by using 1, 7, 7, 7, 7
- Next by thread: Re: make 100 by using 1, 7, 7, 7, 7
- Index(es):
