document.write( "Question 205934: I'm confused on how to solve this.\r
\n" ); document.write( "\n" ); document.write( "I know i can add it in a calculator bat it would be so long.\r
\n" ); document.write( "\n" ); document.write( "I don't know the formula.\r
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\n" ); document.write( "\n" ); document.write( "Find the sum: 1 + 2 + 3 ...+ 99 + 100.
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Algebra.Com's Answer #155528 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Use the formula \r
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\n" ); document.write( "\n" ); document.write( "In your case, \r
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\n" ); document.write( "\n" ); document.write( "So \r
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\n" ); document.write( "\n" ); document.write( "Note: you can verify this answer by adding up each number in the sequence (if you're bored), OR you can notice that 1+100=101, 2+99=101, 3+98=101, etc... and notice that there are 50 of these pairings (half of 100). This means that 50*101=5050.
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