Jerry had some action figures on a shelf in his room. Later he added 7 more action figures to the shelf. If there are a total of 10 action figures on his shelf now how many action figures did he have initially on the shelf?
Let's say that Jerry had $x$ action figures on the shelf initially. 

Then, after adding 7 more action figures, he has $x+7$ action figures on the shelf. 

Now we know that there are 10 action figures on the shelf, so we can write: 

$$x+7=10$$

We can solve this equation for $x$: 

$$x=10-7=3$$

So Jerry had 3 action figures on the shelf initially.