Resizing the spreadsheet (unless you're just changing a column width) relocates all the cell-references in formulas so they still refer to the same cells. If a formula mentioned B1 and you insert a new first row, the formula will now mention B2.
If you delete a cell that a formula refers to, the cell-symbol is
deleted from the formula, so
(+ A1 B1 C1) after deleting the third
(+ A1 B1). In case this is not what you wanted: