If you want to calculate the sum or total when working with cell data located in multiple worksheets, this article write for you!
To sum the same range in one or more sheets, you can use the SUM formula with a special syntax called a “3d reference”.
A reference that refers to the same cell or range on multiple sheets is called a 3-D reference. A 3-D reference is a useful and convenient way to reference several worksheets that follow the same pattern and cells on each worksheet contain the same type of data, such as when you consolidate budget data from different departments in your organization.
That will sum B3 of Sheet1 and B3 of Sheet2
8 + 11 = 19