Setting: 8th grade algebra classroom.

Me: So what is revenue?
Students: It’s the money you make.
Me: So revenue is profit.
Students: Yeah.
Me: No No No! Revenue is not profit. What is revenue?
Student Alpha: It is the money you make before you pay your bills.
Me: OK so what is profit?
Students: It is revenue minus bills.
Me: Revenue is never the same as profit.
Student Beta: Yes it can be!
Me: How?
Student: We could collect up a bunch of rocks and sell them!
Me: No no no! Now you sound like my six year old! “Let’s collect up some rocks and sell them!” No one wants to buy your rocks! Gah! Moving on. Someone express these ideas using the functions we built.
Student Gamma: P(t) = R(t) – B(t).
Me: Thank you.