What is the "partial sums method"

I searched Google under the key words ""partial sums method"" to get these possible sources:

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http://www.nychold.com/em-arith.html
http://72.14.253.104/search?q=cache:nEDq676Ib6QJ:www.bay3tv.com/MathShow/Summing%2520it%2520up%2520Addition.pdf+%22partial+sums+method%22&hl=en&ct=clnk&cd=5&gl=us&client=safari

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.

I hope this helps. Thanks for asking.