A math teacher in Roxana, Illinois has raised eyebrows—and the heart rates of his students’ parents—with an in-class exercise that asked students to calculate how high they’d still be a few hours after ingesting cocaine.

“You take 600 mg of cocaine, your body filters out 40% per hour,” the question read. “How high are you in three hours?”

The question was deemed inappropriate for high school freshmen trying to learn math. While some might shake off this question as an edgy attempt to inject toxicology into an arithmetic lesson, the follow up question seemed less innocent—students were asked to exercise their criminal imaginations in calculating a payment plan to close a debt to their drug dealer over time.

The Roxana school district apologized for the teacher’s drug-assisted teaching methods, releasing the following statement:

“Student welfare is always the Roxana School District's #1 priority. Unfortunately, unacceptable examples were used in a high school math class causing some parent and student distress. The district views the use of yesterday's classroom examples as a demonstration of poor judgment. The district is addressing the matter with the faculty member and those impacted by this incident. The faculty member has apologized to students and parents for this lapse in judgment and has reiterated the intent was never to promote or make light of illicit drug use. The district is taking the necessary measures to ensure that the damage is repaired. The district is addressing this issue as a personnel matter according to district policy.”

Some parents were upset to hear this kind of example being used by a teacher at school.

"Wow. That's a school math problem?" said Christy Scott, a parent of a student at Roxana Senior High School. “We don't need to be teaching children how long it takes to filter cocaine out of their bodies. That is ridiculous. That is not what we should be doing. We should be preventing this and not teaching them how to get rid of it.”

As expected, news of the problem spread like wildfire and it was not long before student Joseph Saban, who is not in that particular math class, heard about it.

“Immediately, I was thinking really? This actually happened? I would not expect a teacher to be using drugs as an example for a problem,” said Saban, trying to figure out how this could have happened. “Either he was trying to relate in some way with the kids, be funny or something like that.”

While the question seems beyond comprehension, it is far from the most offensive math problem, which comes from an Alabama middle school teacher:

“Tyrone knocked up 4 girls in the gang. There are 20 girls in his gang. What is the exact percentage of girls Tyrone knocked up?”