en.wikipedia.org/wiki/Summation

In mathematics, summation (capital Greek sigma symbol: ∑) is the addition of a sequence of numbers; the result is their sum or total. ... Because addition is associative, the sum does not depend on how the additions are grouped, for .... The "i = m" under the summation symbol means that the index i starts out equal to m.

www.dictionary.com/browse/sum

Sum definition, the aggregate of two or more numbers, magnitudes, quantities, ... by or as if by the mathematical process of addition: The sum of 6 and 8 is 14. ... the sum at the top, rather than at the bottom as we do now (cf. the bottom line).

www.mathsisfun.com/definitions/sum.html

The result of adding two or more numbers. Example: 9 is the sum of 2, 4 and 3 ( because 2 + 4 + 3 = 9). Drag the numerals to the two blue boxes to sum them:.

www.quora.com/What-does-sum-mean-in-math-classes

'Sum' means summation,it means addition. In mathematics,we have symbol for the summation i.e,capital Greek sigma symbol '∑'.summation is the addition of a ...

www.reference.com/math/sum-mean-math-dbc05121ea536e63

In mathematics, adding numbers, items or amounts produces a sum. The word also refers to a group of arithmetic problems given as a classroom assignment.

www.columbia.edu/itc/sipa/math/summation.html

Often mathematical formulae require the addition of many variables ... This expression means sum the values of x, starting at x1 and ending with xn. ... which does not involve the variable of summation and the sum involves n elements.

www.mathwords.com/s/sum.htm

Sum. The result of adding a set of numbers or algebraic expressions. this page updated 21-feb-16. Mathwords: Terms and Formulas from Algebra I to Calculus

mathforum.org/library/drmath/view/53078.html

Well - we are told that twice one number is 4 more than four times the other number. But what does that mean? It means that when we take the ...

www.khanacademy.org/math/algebra2/sequences-and-series/copy-of-sigma-notation/v/sigma-notation-sum

No, the sum notation does not accept negative number, fraction or decimal. .... Correct; also, I think you mean Sigma when you are referring to the "Greek letter".