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#1 2008-11-02 06:46:30

tony123
Full Member

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how many

It is possible to replace each of the signs below by either – or + so that

1 2 3 4 ... 96 = 1996.

At most how many of the signs can be replaced by a + sign?

 

#2 2008-11-02 07:06:44

mathsyperson
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Re: how many

1+2+3+4+5+...+76 - 77 + 78+...+82 - 83 - 84 - ... - 95 - 96 = 1996.
ie. there are + signs before the numbers from 1 to 82 inclusive, except for 77.

This means that the maximum number of + signs in the equation is 81.


Why did the vector cross the road?
It wanted to be normal.
 

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