How to select multiple range with arrow key after entering forumula

[PP3321]

Hi all thank you in advance for reading this post.
I want to do sum(range)+sum(range) in 1 cell.

It seems after entering the formula, it does not allow you to add new range by using arrow key.
(Using mouse works)

I want to do this without using mouse.

Is it possible?

 

[GraH - Guido]

Press F2 again.... Look at the left bottom of Excel. You'll toggle EDIT + ENTER mode. Only with EDIT you can go into POINT mode: where you can leave the cell and "point" or select a cell/range.

 

[PP3321]

@GraH - Guido
Thank you so much! It works!