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Here's my problem: say we have four sets of letters (abcdef) (abde) (abc) (ad). We can only add or subtract those sets in a way that (abc) + (ad) = (aabcd), (abcdef) - (abde) = (cf), but (abc) - (ad) is not allowed. Is it possible to get (b) only with these rules?

(inspired by a "find an area" geometry problem) (is there a tag for these specific types of problems?)

hecxagon
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  • The (abcdef) set is useless because it is the only set that has an 'f'. You would have to add and subtract that set an equal number of times for there to be no 'f' in the final result. I expect the answer to your question about getting (b) only is that it is impossible. – DreiCleaner Jul 01 '20 at 14:27
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Expanding on my comment, once we see that we can't use (abcdef) at all, of the remaining sets (abc) is the only one that has a 'c', and (abde) is the only one that has an 'e', rendering both of those useless.

The remaining set is (ad) and obviously we can't get (b) by itself.

DreiCleaner
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