Sunday, July 19, 2009

The Hunt for 24

A very interesting mathematical diversion found through the xkcd fora. The idea is to take any four numbers, all between 1 and 9, and try to make them add up to 24 using only the four basic operators (+-*/). For example, {1,2,3,4} can use 1*2*3*4=24 or (1+3)*(2+4)=24 or (1+2+3)*4=24 or so on.

{3,3,8,8} is a hard one. Highlight the next few lines for the solution.

8*(3-(8/3))=24

A few like {1,1,1,1} don't have solutions, but I conjecture that they all include at least one and mostly multiple 1s.

interesting article on the subject.

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