As I am typing along in Excel, I find it a bother to take my hands off the keyboard and fumble for the mouse. Thus, I will often use the keyboard to make selections. I simply hold down the Shift key and use the arrow keys to expand my selection. As I do so, Excel obliges me by reporting, in the Name box, the number of rows and columns I have selected.
The problem is, once I let go of the Shift key, the contents of the Name box return to normal, and I can no longer tell how many rows and columns I selected. To solve this, I find it very easy to again hold down the Shift key and press one of the arrow keys. This expands the selected range and again reports the selection size in the Name box. If I immediately press the opposite arrow key (while still holding down the Shift key), the selection returns to my original size and I can see the size of that selection in the Name box.