I don't know what the "act it out" strategy is but I will try to help based on my knowledge.
Try this: Write down the numbers 1-4. Then make number combinations with 3 of those 4 numbers. See how many you can make with out repeating a combination. Even it is in a different order. How ever many combinations you can mane is your answer.
This is how I would do it.
Let me know if this helps or not.
Good Luck