33 campers went rowing in the morning. 37 campers went rowing in the afternoon. How many more campers went rowing in the afternoon than in the morning?
There were 33 campers rowing in the morning. 
Then, we're told that 37 campers went rowing in the afternoon. 
We want to know how many more campers went rowing in the afternoon than in the morning. 

To solve this, we can subtract the number of campers rowing in the morning from the number of campers rowing in the afternoon: 

37 - 33 = 4 

This means that 4 more campers went rowing in the afternoon than in the morning.