What formula should you use when adding a lot of numbers?

When adding a lot of numbers, you can use the formula for the sum of a series, which is expressed as ( S = a_1 + a_2 + a_3 + ... + a_n ), where ( S ) is the sum and ( a_1, a_2, ..., a_n ) represent the numbers being added. For large datasets, using the arithmetic mean can also be helpful, calculated as ( \text{Mean} = \frac{S}{n} ), where ( n ) is the total count of numbers. Additionally, in programming or spreadsheet software, functions like SUM() can efficiently compute the total.