Predict what a copied formula becomes
80%
SUM
If you can predict the shift, you can debug almost any broken column in a spreadsheet, because the overwhelming majority of them are broken by a reference that moved when it should have stayed, or stayed when it should have moved.
The rule, once more: copying down adds to the row numbers, copying right advances the column letters, and anything behind a dollar sign does not budge.
D2 holds =SUM(B2:B7). Work out what that formula becomes when it is copied one row down, and type that formula into D3 yourself.
The grid for this exercise needs a free profile.
Everything above is yours to read either way. 19 exercises stay open with no profile at all.