What's a formula for Excel to give a sum?

Answer 1

=SUM(cell range)

EX.

=SUM(a1:a10)

the colon separates the starting cell from the ending cell

Answer 2

You can get the total of a range of cells by doing the following:

=SUM(A1:A6)

An example is given below:

Thus, cells A1 to A6 contains values and cell A7 contains the SUM formula to all values in cells A1 to A6