When large number of data are concerned, then summation is needed quite often. To write a very large number, summation notation is useful. The sequence [1,2,4,2..] whose value is the sum of the each number in the sequence is summation. In simple words, summation notation helps write a short form for addition of very large number of data. We use this symbol –
We use this symbol – , called sigma to denote summation. When a sequence is needed to add from left to right, it could run intermediate result in a partial sum, running total or prefix sum.
The form in which the summation notation is used:
To make it clear, read what each notation in the summation formula stands for:
This expression is read as “The sum of x sub i from i equals 1 to n”.