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Where cells A3 to A12 each hold the cell above plus one, the ten equations become:

$A|_{i=3}^{12} = A_{i-1} + 1$

• The label on the left names the run by its column and its rows.
• Every reference inside the equation is written as an offset from the indexed row, so =A2+1 in row 3 and =A11+1 in row 12 are recognised as the same statement.
• In Name mode the label is the family's name rather than the column, as in $Mass|_{i=1}^{6}$. The range given is the range of the name's index, which is not always the range of rows: a column labelled at row 2 has its first value at row 3 and calls it 1.

Usage

• Switched on by default. To turn it off, open Settings in the panel and clear Group table expressions.
• Needs a range selected. Grouping is a judgement about several cells at once, so selecting a single cell renders it on its own as it always did.
• Applies to Ref and Name. Value is left alone: the values down a table are all different, and the one thing a grouped equation cannot show is ten different numbers.
• The run must be unbroken. A gap, or a cell holding something else, starts a new group rather than widening this one.
• The equation is placed vertically centred on the whole run rather than beside its first row, so it reads as belonging to the table rather than to the top of it.
• Use Trace to see which cells a grouped equation stands for: the run is marked down its edge in a colour, and its equation is bordered to match.

How two formulas are recognised as one

The work is in deciding that two formulas are the same formula. =A3+1 and =A4+1 differ as text and not at all as meaning, so each is rewritten with its references as offsets from its own cell — the form Excel itself stores — and the rewritten strings are compared.

A reference fixed with a $ is an exception: =$A$1*B3 and =$A$1*B4 still group, because the anchored part means the same cell in every row and only the relative part varies.