This one is giving me a hard time
In a large high school, some teachers teach only 1 subject, and some teachers teach more than 1 subject. Using the information given in the table below about the math, science, and gym teachers in the school, how many teachers teach math only?
12 taught at least 1 class of math
10 taught at least 1 class of gym
20 taught at least 1 class of science
6 taught both gym and science but not math
5 taught both math and science but not gym
2 taught gym only
1 taught math, gym, and science
The answer is 5 but how??? Can someone help me figure this one out please, is there a way to make a table or something to display what's going on?