You can solve this question by setting up an equation. Dan has twice as many stickers as Cam does. We can call Dan 2x, and Cam x. So the equation would be:
2x-15=x+22.
Then solve this equation:
Add 15 on both sides
2x=x+37
Subtract x on both sides
2x-x=37
X=37.
Therefore Cam has 37 stickers, and Dan has 74 stickers.