sum
Notations of sum
Sum represents the n-ary addition operator.
Descriptions of this symbol
- OpenMath's arith1/sum
- Sum in MathML3
- Sum in MathWorld
Observations of sum
Arabic
The math book for high school in Saudi Arabia, Kuwait and some provinces represents summation symbol in Arabic context.
Download the book and find the example in page 156.
In Jordan and some other provinces we find the Arabic book Union Councils Of Scientific Arabic Language
also represents summation as we see in the example on the right.
The big two letters '?' means sum symbol, '?' for the upper bound of summation and '?' is the index of summation.
Dutch 
In Dutch book Basisboek Wiskunde we see the summation symbol shown in page 69. Download the book and find the example.
German 
We see in the German book Höhere Mathematik mit Mathematica the example represents summation symbol in german context.
Download the scanned pages and find the example in page 11.
French 
The french book Introduction aux mathématiques discrètes shows the summation symbol in page 10.
Go Directly to the example.
English 
The example in the American book The Art of Combinatorial Proof represents the binomial summation in page 68.
Find the example in google books link.
Finnish 
We find the Finnish book MAOL-taulukot shows sum symbol with the example in page 11. and it is called 'Summa' in Finnish context.
Download and preview the book.