What function should be entered into B7 to calculate the total budget

=SUM (B3:B6)

In excel we have two options to calculate a total budget, for example, we're going to assume that we have 3 values A6, B6, C6, In this case, we can use this formula = A6+B6+C6 or = SUM (A6:C6), in both ways we're going to have the same result because this is a sum but with different formulas, even we can select specific rows, is not necessary to add range.