A couple of rarely used features of worksheet formulas are Unions and Intersects.
Most Excel users have probably have come across Union – the combination of ranges to be treated as one range. eg. =SUM(A1, A5:A11, C10)
If you start by typing the formula =SUM( then hold down CTRL and select ranges, Excel automatically defines a Union for you.
The ranges are separated by a comma. The comma is referred to as a Union operator.
I’ve seen Unions used for a Grand Total by summing Sub Totals
Just like the Union operator is a comma, the Intersect operator is a space.
When you separate ranges with a space then the range used is where they intersect. eg. =A1:C1 B1:B3 will return the same result as =B1
I’ve never seen Intersects used in the wild. I’ve only recently discovered it myself.
It’s interesting to note that in this sample changing Feb to Jan =SUM((Apple, Banana) Jan) does not result in a Circular Reference.