double selections

[alshaikh03]

What is the benefit of cumulative selection (double selections)
In one cell?

[#2]

Basically, it finds the difference between one cell to another, then able to fill sequence drag plus button For example, Cell A1 has 1, A2 2, A3 3 selecting three A1, A2 & A3 with mouse, then drag right side down plus button, will give sequence like 4,5,6,7,8 until the cursor moved. Same way type Sunday, Monday, Tuesday Select and drag it downside, will give result of Wednesday Thursday like that Hope I have given correct explanation

[#3]

Thank you Sivakumarrj.

I had a question about click twice or more on one cell to select it more than once
As in the attached picture, the cell H8 shaded in a darker color more than more than the cell H7 and H6