Question

what exactly is summation notation?

is that like the same thing as sigma notation?

Answer 1

I searched Google under the key words "'summation notation'" to get these possible sources:

http://davidmlane.com/hyperstat/A46748.html
http://en.wikipedia.org/wiki/Sum
http://www.math.ucdavis.edu/~kouba/CalcTwoDIRECTORY/summationdirectory/Summation.html

You decide. 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.