Difference between revisions of "Main Page"

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__NOTOC__  __NOEDITSECTION__  <div class="frontlink" style="background-color:#204079; color:#ffffff; font-size: 110%; padding-left:15px; padding-right:15px; padding-bottom:10px;  margin-left: 5px; box-shadow: 2px 2px 6px #ccc;"> <span style="font-size: 200%">'''Welcome to the AoPS Wiki!'''</span>
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__NOTOC__  __NOEDITSECTION__  <div class="frontlink" style="background-color:#204079; color:#ffffff; font-size: 110%; padding-left:15px; padding-right:15px; padding-bottom:10px;"> <span style="font-size: 200%">'''Welcome to the AoPS Wiki!'''</span>
 
   
 
   
 
The AoPS Wiki project is administered by the [[Art_of_Problem_Solving|<span style="color:#83a1d6;">Art of Problem Solving</span>]] for supporting educational content useful to avid math students.  
 
The AoPS Wiki project is administered by the [[Art_of_Problem_Solving|<span style="color:#83a1d6;">Art of Problem Solving</span>]] for supporting educational content useful to avid math students.  
 
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<div class="frontlink" style="background-color:darkred; color:#ffffff; padding: 10px; margin: 10px 0;">The wiki is currently not editable. It is currently scheduled to be editable again on November 21, but this date is subject to change.
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Revision as of 15:45, 15 November 2018

Problem of the Week

1983 AIME, Problem 13

For $\{1, 2, 3, \ldots, n\}$ and each of its non-empty subsets a unique alternating sum is defined as follows. Arrange the numbers in the subset in decreasing order and then, beginning with the largest, alternately add and subtract successive numbers. For example, the alternating sum for $\{1, 2, 3, 6,9\}$ is $9-6+3-2+1=5$ and for $\{5\}$ it is simply $5$. Find the sum of all such alternating sums for $n=7$.


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