Because by doing so, any data entry or formatting change you make in a range in one grouped sheet
will be reproduced in precisely the same range in all the other grouped sheets, affording you a highly
efficient way to achieve the same data arrangement and look across sheets. Thus if you enter a series
of header rows in one grouped sheet—say, Name, Address, and Age—all those entries will appear in
the same addresses on the other sheets.
To group sheets, click on the first one you want to group. You’re then handed two group options: If
you want to group non-adjacent sheets in a workbook, press Ctrl, leave that key down, and then click
sheet tabs. To select all the sheets in the workbook, you can right-click any sheet tab and click b.
To demonstrate, open a new blank workbook and click the tab of Sheet1. Press Shift and at the
same time click the Sheet3 tab (yes; you could have also clicked Select All Sheets, as per the instructions
in the last paragraph). All three tabs should appear white (or at least whiter than usual, in the event
you’ve colored any tabs), with the tab text “Sheet 1” appearing in boldface, indicating it is the active
sheet. Then in cell A1 type Name, then Address and Age in cells B1 and C1, respectively. Then click
Sheets 2 and 3—and you’ll see the same data in the same cells. To deselect, or ungroup, the sheets,
right-click any tab and click Ungroup Sheets (another dorky verb), or click on any sheet that is not
cur r e n tl y g r oupe d.