Sunday, October 9, 2011

Solution To: Four Fours

Here is the original problem:
Four Fours
How many numbers can you represent using four 4's and any available operation?

For example, here is the representation for the number 0:
0 = 44 - 44
See how the representation contains four 4's
Find the representation for the numbers 1 through 10.


Solution:
This problem is an interesting problem in that there isn't just one solution.  Here is the solution that one person gave:
1 = (4/4)+4-4
2 = (4*4)/(4+4)
3 = (4+4+4)/4
4 = ((4-4)/4)+4
5 = ((4*4)+4)/4
6 = ((4+4)/4)+4
7 = 4+4-(4/4)
8 = 4+4+4-4
9 = 4+4+(4/4)
10 = (44-4)/4
 
And while her answer is correct, it isn't an the only correct solution.  For example the number one could also be represented in this way:  1 = (4+4)/(4+4) (and there are other solutions).  2 could be represented in this way: 2 = (4/4)+(4/4).  You see where I am going with this.  There are in fact many solutions to this problem.
 
Sincerely,
The Math Freak
 
 


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