Moving runs
FreeCell only ever moves one card at a time. Dragging a run works because the game performs those single moves for you — so a run goes exactly when you had the room to carry it card by card.
What the number counts
(1 + empty free cells) × 2^(empty columns). The cells hold cards one at a time; each empty column can hold a stack, which is why it multiplies instead of adding.
The half people forget
Moving into an empty column carries one fewer, because that column cannot help carry the run it is receiving. Three cells and one empty column moves eight cards onto an occupied pile but only four into the empty one. This is the single most common surprise in the game, and it is why the board keeps the number in front of you.
Runs are not the goal
Building a long ordered run feels productive and often is not: it locks cards together that you may need to separate. Build a run when you have somewhere to send it.
On the board, this one reads: Move all 4 of them as one run — your limit of 5 allows it.