+42 
I'm confused about how to set it up correctly and how to complete it.
+23252 "Out of 40 students" -- that's your total-total; put that into the lower-right-hand box
"14 are taking calculus" -- that's the total for the "taking calculs" column; put that in.
Now, you can find the total for all those "not taking calculus"
"29 are taking biology" -- that's the total for the "taking biology" row; put that in
Now, you can find the total for all those "not taking biology"
5 are taking both" -- that fills in the box for those that are taking both calculus and biology; put that in.
Now, you can complete the table ...
