Answer:
n = 39
Explanation:
To find what n equals, I want to get it alone on one side of the equation. 
To do this, I move 13 to the right side of the equation by subtracting 13 from both sides. 
13-13=0 so n is the only value on the left side
52-13=39. 
You are now left with n = 39
To check that this is right, add 13 to 39. It equals 52, so you know the answer you found is correct.