The point of using this formula in the checking register is to make the table so it can be sorted without messing up the "balance" column. The formula takes the starting balance and adds to it the sum of the entries in the "Amount" column starting at the topmost row and stopping at the current row.
You preferences in Numbers is to "Use header cells as cell references". "Balance 101" = the cell that has "Balance" in the header row and "101" in the header column. In other words, it is cell F3.
OFFSET(base, row offset, column offset, rows, columns)
Offset can give you a single cell or a range of cells. In this case it is giving you a range of cells.
Base = cell F3, as described above. The cell with the formula in it
Row Offset = 3-ROW()
- For the first entry in cell F3, it is 3-3 = 0 = no offset = the current row = row 3.
- For the second entry, F4, it is 3-4 = -1 = one row up = row 3
- For the third entry, F5, it is 3-5 = -2 = two rows up = row 3
- See the pattern. Always row 3
Column Offset = -1 = one column to the left of the base = the "Amount" column
So, the offset is to the cell in the "Amount" column in row 3 = cell E3
Rows is an optional parameter if you want the result to be a range. It specifies how many rows to include in the range
- For the first entry in cell F3, ROW()-2 = 3-2 = 1 = include only one cell. The result is therefore cell E3.
- For the second entry, cell F4, ROW()-2 = 4-2 = 2 = include two cells. The resulting range is therefore E3:E4
- For the third entry, cell F5, ROW()-2 = 5-2 = 3 = include three cells. The range is therefore E3:E5.
Columns is optional. It is not used in this formula. It works like row offset.