In
mathematics,
summation (symbol:
∑) is the
addition of a
sequence of numbers; the result is their
sum or
total. If numbers are added sequentially from left to right, any intermediate result is a
partial sum,
prefix sum, or
running total of the summation. The numbers to be summed (called
addends, or sometimes
summands) may be
integers,
rational numbers,
real numbers, or
complex numbers. Besides numbers, other types of values can be added as well:
vectors,
matrices,
polynomials and, in general, elements of any
additive group (or even
monoid). For finite sequences of such elements, summation always produces a well-defined sum.