You may know that when you’re selecitng cells in Excel with the mouse, pressing the Ctrl button as you click adds the selected cells to the selection.
But, there’s an easier way. First, let’s try “Extend Mode” with F8. If you press F8, you enter Extend Mode, and now the arrow keys will extend the selection. (Of course, we already covered here that pressing Shift when you use the arrow keys does the same thing without messing around with the F8 key.)
However, this next bit’s useful. If you press Shift+F8, then you lock in the current group of selected cells, and can use the arrow keys to move to another area, and then select new cells (either using the normal Shift select method or Extend Mode).
Once the cells are selected, you can do whatever you like to them, such as bold with Ctrl+B.