Returns the number of individual ranges that belong to a multiple range. A range can consist of contiguous cells or a single cell.
Reference represents the reference to a cell or cell range.
The function expects a single argument. If you state multiple ranges, you must enclose them into additional parentheses. Multiple ranges can be entered using the semicolon (;) as divider, but this gets automatically converted to the tilde (~) operator. The tilde is used to join ranges.
=AREAS((A1:B3;F2;G1)) returns 3, as it is a reference to three cells and/or areas. After entry this gets converted to =AREAS((A1:B3~F2~G1)).
=AREAS(All) returns 1 if you have defined an area named All under Data > Define Range.