Click on the first sheet you want to insert a row into. Hold the SHIFT key
down and click on the last sheet. All the sheets in between plus the two you
clicked are now "grouped" and all should be highlighted. Any change made on
one is mirrored in them all.
So, on the sheet still visible, insert the row you want and do any
formatting necessary. Then right-click on a sheet tab and UNGROUP them.
