6 campers went rowing in the morning. 47 campers went rowing in the afternoon. How many more campers went rowing in the afternoon than in the morning?
There are a total of 53 campers that went rowing. 
6 went rowing in the morning, which means that 47 went rowing in the afternoon. 
47 is 9 more than 6, so 9 more campers went rowing in the afternoon.