The correct formula that is going to add up the values in the listed cells is =A1+A2+A3+A4+A5.
This formula will add up the individual values in each of the five cells and put the answer in the cell where you enter the formula.
Another formula that you can use to get the same value is to use the =SUM function. By entering =SUM(A1:A5) in the cell it will generate the total of all of the values in the cells between A1 and A5.