The responses I received from my friends to âIâm about to interview Erez Sheiner for the blogâ were as follows: People who didnât know Erez wondered what does it have to do with Cup of Code and people who did know, were thrilled to see the final result.
Dr. Erez Sheiner is a lecturer in the math department of Bar Ilan University. He teaches in the CS (computer science) department as well, where he wins âbest lecturerâ almost every semester. Erez also has a successful youtube channel dedicated to math and a TikTok account! On Facebook, he is a top fan of the popular pageâââBIU (Bar-Ilan University) confessions. This page posts anonymous messages and people comment on them, and you get a top fan badge if you are active and comment a lot.
I told you he is not your ordinary lecturer. This is an exciting opportunity to ask so many questions! So now you know why I was so curious.
Donât miss the last blog-post, where we talked about academia, student life, short-term boot camps, work-life balance, and more!
Iâll start with a question that isnât specifically about you, but I was curious about: We see you teaching in classâââbut what does your typical day look like?
I, unlike most of the professors, am in a teaching position and not research. This means that most of my activity is teaching.
Also, well⌠One might not call this research but I constantly try to find new ways to prove lemmas and write new exercises. Iâve recently built some cool mini-games for the game theory class I gave to high schoolers.
I actually saw that lecture you mentioned, after getting recommendations from a friend.
Oh really? And did you see how amazing they are? How they participate? Because it is a chosen course and not mandatory, I only have students that want to be there. Also, these are high schoolers so they are young and energetic, and donât give me the feeling that they do me a favor by showing up to class.
Well, about that: Where do you find the motivation to invest time and effort in us, when students often give the feeling they donât care to listen?
Well, the answer is quite simpleââânarcissism. I love seeing the studentâs feedback at the end of the year. Some professors really donât care, but I feel like you are my children, and your success is my success. This is my goal in life. This is what makes me happy.
Speaking of goal in life, I read you said in the past âwith time, knowledge is becoming easier to access, but the teacherâs jobâââto inspireâââwill remain foreverâ. Do you remember the moment it transferred from âteaching is a mandatory part of my jobâ to âteaching is my destinyâ?
Teaching has always been my destiny. I remember myself as a teenager in an educational movement for young people. One day I had two lectures to give. The first group started the lesson thinking A, and I shifted them to think B. The second group was the other way aroundâââstarted thinking B and switched to thinking A! It fascinated me, realizing how much power teaching can have and how impactful you can be.
Truth be told, it doesnât matter if my day started badâââthe moment I enter a classroom I shine. I donât wake up in the morning hating my day. Well, I donât like checking exams, but I do enjoy the teaching part.
For the next question, Iâm gonna quote your toddler Loei, and ask: âWhy are you working? You already received an awardâ. By that I meanâââyou already reached the peak, so what motivates you to keep going?
I did not reach the end goal! Iâm far from it! When I receive the studentsâ feedback at the end of the semester, I make sure to read the negative ones, so I can improve.
More than that, our education systems did not reach the end goal, so how can I? Besides, I do what I do because I love it, not to reach some goals. Every year I try to improve something, I donât just follow old notes without thinking.
Ok, here is the question I kept for 4 years: Why are you wearing suits?! Every day, no matter the temperature outside!
Well, this was a process. I always liked formal wear. It started with wearing T-shirts and ties, then it became a button-up shirt and a tie, and then the 3 piece suit youâve seen me in, in the university.
With that said, there are things that I believe are too much, like a butterfly tie. Youâll never see me wearing a butterfly tie.
Is a butterfly tie too much? Iâm pretty sure the 3 piece suit is already too much.
Is it? It doesnât feel too much for me. This is how people on TV dress up.
To be honest, I donât understand why people care about outfits. For me itâs transparent. I am aware of the fact that people see me, but I dress for myself.
Speaking of people seeing you: You give lectures at University and also on your highly viewed youtube channel. Does it ever worry you that you will make mistakes or say something incorrect?
Absolutely not, and not because I canât be wrong. Because a professor solves the given problem easily, it seems like he is some kind of a magician. Truth is, he solved it easily not because he knows everything, but because he came prepared. I think itâs important to show students HOW you approach a problem, and not just how to solve it.
On the other hand, psychologically itâs hard for students to see their professor making a mistakeâââbecause then they think it is the hardest problem that exists. This is a shame because thatâs not true.
Continuing the topic of fear, what about potential mistakes that donât regard your teaching? About a decade ago, you participated in the Israeli version of the reality TV show âCome Dine With Meâ. Aren’t you afraid of the consequences of participating in a reality TV show, or taking this interview, where you donât have control over the output?
The decision to participate in this TV show was stupidity, not courage. I canât bring myself to watch it again, both because I hate how they edited it and also because I said things I wouldnât say today.
In the long term itâs not such a big deal because it doesnât harm me in any way, only creates some buzz. In Bar Ilan, I gave a lecture about my anxiety, and on social media, I make effort to show the negative as well. Itâs important to me to show that we are all humans and nothing is perfect. I know there are students that look up to me, and I want to show them itâs not unreachable.
You mentioned social media. You are very active on a Facebook page named âBIU confessionsâ, where people post anonymous questions and thoughts. One comment you wrote really stuck with me. Someone was anonymously sharing his frustration that he didnât find the woman that he will know is his soulmate at first sight. To that, you responded: âa soulmate isnât found, she is made. Itâs your journey together that makes her your soulmateâ
Iâm glad to hear that. Thatâs also why I love teaching because people interpret it and apply it to their own lives.
With that said, arenât you afraid that being active on social media will lower the respect for you among your students?
I never had distance from students. Respect is not earned from the title. I think the majority of the students appreciate it when you get to their level.
The posts on this page are about ALL subjects, including inappropriate ones. Are there any red lines you decided for yourself that you wonât cross?
This is an issue I find myself wondering about. I ask for my wifeâs opinion sometimes. A general guideline is not to be too aggressive and not to harass anyone. I check myself based on the feedback I receive.
Also, I try not to get into arguments, and if I doâââI say something objective. To be clear, I am not afraid that Iâll embarrass myself, but I worry that Iâll make someone else feel uncomfortable.
Arenât you concerned by the fact that you are the only lecturer that is communicating with us on social media?
Why should I be concerned? Itâs amazing!

[source: https://www.facebook.com/sheiner]
But you are the only one. Maybe itâs not professional?
Being friendly with my students on Facebook doesnât mean Iâm not giving them the grades that reflect their knowledge. I am professional, and I have proof of it. There are people out there who think itâs inappropriate, but the people who matterâââ to me and to my careerâââdonât think so. They appreciate me and I donât mind about the rest.
As I mentioned before, Iâve started watching your game theory course. Iâve noticed something that I donât remember as a studentâ this time there was more effort making gender-equal language and examples (note for readers: The Hebrew language is gendered).
Yes, it is pretty new. But itâs not just me changing, itâs the whole world. The conversation online has developed and I read. I learn, I fix where I can, but I wonât define myself as a feminism activist. Also, there are things people are doing that I think are extreme, like sending a boy in a dress to school. They do it for their agenda and the kid will pay the price.
Last question: While watching your youtube videos, I couldnât help but wonder âââwhy are you giving it for free? You have good content and you can make money out of it.
I do not believe that sharing for free takes something from me. For example, we have full-length university lectures recorded and uploaded to YouTube for students that couldnât or didnât want to come to class (pre-COVID19 era). The ones against this idea said that this action will make the classrooms empty, but itâs not true, my classrooms are still full. As in music, live performance is better than the record, even though the record is better quality.
Besides, there are benefits that are not financial, like being recognized in the streets, or knowing that my videos help students. I believe we should spread knowledge as much as possible. Money isnât everything.
What a great way to end this interview! I also believe in spreading knowledge and helping each other. This is what Iâm doing here on my blog. I hope you enjoyed reading this at least as much as I enjoyed talking to Erez.
Thank you!