Question

find the sum and give step by step explanation please​

Answer 1

Answer:

plz send it clearly I can't understand

Answer 2

Answer:

The symbol Σ (sigma) is generally used to denote a sum of multiple terms. This symbol is generally accompanied by an index that varies to encompass all terms that must be considered in the sum. For example, the sum of first whole numbers can be represented in the following manner: 1 2 3 ⋯.