9 campers went rowing and 4 campers went hiking in the morning. 33 campers went rowing in the afternoon. How many campers went rowing and hiking in all?
There are 9 campers who went rowing in the morning and 4 campers who went hiking in the morning. 

There are 33 campers who went rowing in the afternoon. 

There are a total of 9 + 33 = 42 campers who went rowing at some point during the day. 

There are a total of 4 + 33 = 37 campers who went hiking at some point during the day. 

There are a total of 42 + 37 = 79 campers who went rowing and hiking in all.