Jung Kyung Ho practiced math for weeks so Crash Course in Romance’s Choi Chi Yeol was authentic

When you watch Jung Kyung Ho play celebrity math instructor Choi Chi Yeol, it probably didn’t dawn on you just how much work he had to do in the weeks leading up to filming Crash Course in Romance so that his portrayal of the math whiz was authentic.

After all, like most of us, Korean actor Jung Kyung Ho isn’t a math genius himself.

In a new Behind the Scenes of Crash Course in Romance video from Korean TV channel tvN, however, we learn not only did Jung Kyung Ho buy a blackboard and practice on it at home, he also studied for weeks so, when he stood up in front of a class of teenagers as Choi Chi Yeol, he actually looked like a math instructor.

And not just an actor playing one.

From being able to write the complicated math equations on the board, to being able to explain them to the more than 20 teenagers sitting in his “class”, all of it required a heckuva lot of work.

Especially when, just one missplaced symbol on the blackboard as he writes and talks would have actual math geniuses screaming at their TV screens about what an idiot he is, and how ridiculous the show.

In the video, Jung Kyung Ho himself talks about how he tried to understand the math equations he would have to write on the board, but figured out quickly he couldn’t.

That meant he had to memorize every formula instead.

That way he would then be able to write each mathematical formula on the board, and make Choi Chi Yeol look like an incredibly talented math instructor while doing it. Yikes!

The producers of the utterly superb Korean drama Crash Course in Romance even went one step further, and hired an actual high school math teacher to consult on set.

They could then ensure every mathematical equation was correct, and that Jung Kyung Ho explained them as a real math instructor would.


In the Behind the Scenes video the teacher explains, while he had seen other dramas centering around teachers, he was impressed with the way Crash Course in Romance was filmed, as it showed the reality of being a hardworking math instructor.

Including having to stay up all night to be prepared for the following day’s classes.

With his help, and with the hard work Jung Kyung Ho put in before filming of Crash Course in Romance began, it is no wonder the Korean drama is one of the top shows in the country right now.

Even though, Jung Kyung Ho admits he was incredibly nervous before filming began, he is also very pleased at how well it turned out.

Finally, to make sure you know just how much he cares about everyone watching Crash Course in Romance, the actor warns that the weather is very cold, so make sure you are careful not to catch a cold. Awwwwwww.

Watch Jung Kyung Ho in the Behind the Scenes of Crash Course in Romance video below.

It sadly lacks English subtitles but, if you don’t speak Korean, you can click the auto-generated subtitles option and choose “English”. With that, you can at least understand the guist.

But, even without it, you can still see just how hard Jung Kyung Ho worked to make Choi Chi Yeol a character you would love.

RELATED: The 8th episode of Crash Course in Romance earns an even larger audience than the previous episode


About Michelle Topham

Brit-American journalist based in Austria, former radio DJ at 97X WOXY, and Founder/CEO of Leo Sigh. I've covered anime, manga, K-drama and music news for over a decade.