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Our Team

Our specially trained math instructors will teach your child how to understand math in an individual setting; our unique approach enables us to explain concepts really well and lend a helping hand to every student. Our tutors foster a caring, encouraging environment that helps kids thrive and learn! Read below to learn more about our talented team:

Youngkun, Center Director

Youngkun is customer service driven and has a passion for teaching math.  The desire to help make "math make sense to kids" is what brought to Mathnasium in the first place. Youngkun offers outstanding consultative advice to educate parents and students on the Mathnasium program and the academic expectations of kids today with Common Core standards. Knowing success breeds success, Youngkun's team will help design a learning plan just right for each student so they can meet their math goals in an efficient manner. You can always schedule a time to meet with youngkun to discuss your student and their mathematical progress by clicking


Jeremy,  Assistant Center Director

Jeremy is a math major at Cal State San Marcos. He is a TA on campus for his peers and an a valuable asset to our center - teaching math in a manner that makes sense to younger kids through Calculus! Having worked at another Mathnasium prior to joining us, Jeremy's knowledge bank on the problems, techniques and strategies of the Mathnasium Method and expectations from school make him an incredible addition to our team.

Aesher, Lead Instructor

Aesher holds a Bachelor's in Environmental Science and an MS Environmental Policy and Management from American Military University. He plans to continue his education further by earning a EED in Higher Education with a focus in STEM and an MBA. He has experience tutoring English, Math, Chemistry, and Biology for over a decade and relocated to the community after having worked at another Mathnasium in Orange County. Aesher makes math fun by utilizing every day situations into math concepts. 

Clair, Lead Instructor

Clair is going into her third year at Miramar College where she is pursuing a major in Interior Design. Clair excels at breaking down Algebra and Geometry concepts for our middle school students. She works hard to make learning math an enjoyable time and it shows in the smiling faces of the kids she spends time with.


Anton, Instructor

Anton recently graduated from high school and will be attending Palomar College in the fall. While new to Mathnasium, he is no stranger to tutoring young children, as he has previous taught kids Russian. In his free time he enjoys acting and working on plays and musical theater productions. Anton is passionate about math and making learning an enjoyable experience  with real world applications.   

Brianna, Instructor

Maryam, Instructor

Mason, Instructor

Anne, Instructor

Karen Lossing is the center director/owner of the math learning center Mathnasium of 4S Ranch.Karen Lossing, Owner

Karen earned a Bachelor's degree in Marketing from Penn State and spent ten years in the business community. After staying home with her kids, she earned her Texas teaching certification and went on to teach third and fifth grades and Special Ed for seven years. In addition, she served on the Response to Intervention team and was a district liaison for Math Curriculum and Instruction. Karen completed her Master's degree in 2010 and, prior to moving to San Diego, served three years on her elementary school's administration team incorporating and facilitating 21st Century learning standards. Karen looks forward to math making sense to all the kids who learn at Mathnasium of 4S Ranch.

Libby, Director of Operations

After a couple years of being a seasonal instructor in our center, Libby recently graduated from UCLA and has joined our team as the Director of Operations. While she is no stranger to the instruction and educational aspects of Mathnasium, Libby focuses on back office functions and the community involvement side of our center. So if you have any school events or sponsorship opportunities you would like Mathnasium of 4S Ranch to be involved in, Libby is your girl!