The accumulation operation is to accumulate the numbers below the accumulation number one by one and follow the operation rules behind the accumulation number.

For example, i= 1 is written under ∑ and i= 10 is written above.

Then there is ∑ (the square of I)

In this way, the sum of squares from 1 to 10 is found.

If you don't write rules, it is the accumulation of positive integers.

If you don't write up and down, it is simply accumulation.