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chris starr
New Member

USA
1 Posts

 Posted - 09/27/2007 :  16:08:52 I am helping my child work on coming up with the number 24 using the follwing 4 numbers. They canbe used in any order, only once.7, 7, -7, 3. You can use addition, subtraction, multiplication or division in the problem.

royhaas
Moderator

USA
3044 Posts

 Posted - 09/27/2007 :  17:43:37 7+7-(-7)+3

tkhunny

USA
1001 Posts

 Posted - 09/28/2007 :  17:41:49 There are 51 ways to do it. They're not quite all the same. The ones on the bottom are a little trickier.a = -7 7+(7+(3-a)) 7+(3+(7-a)) 3+(7+(7-a)) (7+7)+(3-a) (7+3)+(7-a) (3+7)+(7-a) (7-a)+(7+3) (7-a)+(3+7) (3-a)+(7+7) 7+((7+3)-a) 7+((3+7)-a) 3+((7+7)-a) 7+((7-a)+3) 7+((3-a)+7) 3+((7-a)+7) (7+(7+3))-a (7+(3+7))-a (3+(7+7))-a (7+(7-a))+3 (7+(3-a))+7 (3+(7-a))+7 ((7+7)+3)-a ((7+3)+7)-a ((3+7)+7)-a ((7+7)-a)+3 ((7-a)+7)+3 ((7+3)-a)+7 ((3+7)-a)+7 ((7-a)+3)+7 ((3-a)+7)+7 7-(a-(7+3)) 7+(7-(a-3)) 7-(a-(3+7)) 3-(a-(7+7)) 7+(3-(a-7)) 3+(7-(a-7)) (7+7)-(a-3) (7+3)-(a-7) (3+7)-(a-7) (7-(a-7))+3 (7-(a-3))+7 (3-(a-7))+7 7-((a-7)-3) 7-((a-3)-7) 3-((a-7)-7) 3x(7-(7/a)) 3x(7-(a/7)) 3x((7/7)-a) (7-(7/a))x3 (7-(a/7))x3 ((7/7)-a)x3 Have fun.

the_hill1962

USA
1444 Posts

 Posted - 11/05/2007 :  07:12:33 tkhunny, how did you arrive at "there are 51 ways..."? Is there a formula that is used? Did you use a computer program? Did you type all the solutions out by hand?

tkhunny

USA
1001 Posts

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