Explanations are in the references, but to start with:.
ROW() is the current row number
COLUMN() is the current column number
ROW()-1 is the current row number less one
COLUMN()-1 is the current column number less one
=(ROW()-1) + (COLUMN()-1) is the number in each cell for the addition table
=ROW() + COLUMN() -2 is equivalent to the above
$A2 as you fill across the $A reference to column A remains the same
as you fill down the reference to column A remains to same as would anyway.
2 as you fill across the 2 reference to row 2 remains the same
as you fill down the row adjusts accordingly, each row down is one higher
Similar for B$1 except that is the row which is being maintained as absolute.
Still not clear read the references to Absolute and Relative referencing.
the topic in HELP is:
The difference between relative and absolute references
Chip Pearson's page is
Relative And Absolute References
http://www.cpearson.com/excel/relative.htm
References to the Fill Handle and to the formulas used above were on my pages
Populating a Table based on number of rows and columns (#MultTab)
http://www.mvps.org/dmcritchie/excel/join.htm#MultTab
Fill-Handle, Replication and use of the Mouse
http://www.mvps.org/dmcritchie/excel/fillhand.htm
If you switch to the formula view you will see the formulas used in each cell
the shortcut to formula view is Ctrl+` (hold ctrl while accent grave)
Also available through Tools, Options, View (tab), [x] Formulas
Remove the checkmark to toggle back to the normal view.
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