Mathnasium 42020 Village Center Plaza, #100, Stone Ridge VA 20105 (571) 295-5559

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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:


Garry Klegin, Owner

Garry has had a long and successful business career. He holds an MBA and CPA. Garry is a proud father of two adult sons who both attended the University of Virginia. Garry has always been a strong proponent of education and mathematics in particular. Garry is a firm believer in helping all children reach their true potential. Here at Mathnasium, Garry and the rest of the team strive to accomplish a fun and effective learning environment every day.


Branden Klegin, Owner and Center Director

Branden began his career as a licensed stock broker. Over the last several years, Branden has worked as an Instructor and Lead Instructor at various Mathnasium locations in Northern Virginia. It was during this time that Branden saw first-hand how well the Mathnasium Method works. Branden finds it very rewarding to see the students improve their math knowledge while enjoying the learning process along the way. Branden scored a perfect 800 on his math SAT and he specializes in SAT preparation. Branden is currently working towards his Master Instructor Certification.


Karen Cooper, Curriculum Director


Karen has over 20 years of experience in education and holds a Masters Degree in Education and Curriculum Development. Karen has been involved in both the public school system as well as private mathematics instruction. She is very passionate about providing students the best framework for success. Karen is the Curriculum Director and will be working closely with all the Instructors.



Jackson Barbour, Lead Instructor

Jackson is a graduate of The College of William and Mary with a bachelors of science in statistics. He started working at Mathnasium in 2012. He has over four years of experience working with children having spent his high school years as a camp counselor. He now enjoys the opportunity to share his knowledge with students and help them improve their math skills. Outside of work, Jackson is a huge sports fan and loves how pivotal statistics are in his favorite sport, baseball.


David Castiel, Instructor

After a career encompassing both academia and entrepreneurial high-tech ventures, David is delighted to be able to share his love of math and science with young minds. David holds a PhD in Physics and has taught at the college level before pursuing research as a post-doctoral fellow. He also holds several patents related to satellite systems and has been published in scientific, technical and business journals. “If properly taught, Math and Science can be truly enjoyed by everyone.” is David’s guiding principle.


Jack Forrest, Instructor

Jack Forrest attends Dartmouth, where he studies Economics with a minor in Human Centered Design.  He graduated from the Bullis School in Potomac, MD, in 2016, and received the Maryland Merit Scholastic Award for being in the top 5% of the entire graduating class in Maryland.  During his time at Bullis, he completed BC Calculus and Honors Vector Calculus and received the John W. Spencer Award for Excellence in Mathematics as well as the Dartmouth College Book Award and the Bullis Excellence in Music Award.  Jack has a passion for math and mentoring.  As a member of the Bullis Student Tutors program for four years, he grew to love working with kids on a weekly basis and helping to improve their academic performance.  Jack plays Division 1 lacrosse at Dartmouth and has worked with young players as a coach at various lacrosse camps and programs.  He also enjoys playing the violin and was concertmaster and first chair of the Bullis Strings Ensemble.


Simrat Jassal, Instructor


Simrat is currently studying at the Univerity of Virginia. In her Junior year of high school, Simrat scored a 5, the highest mark, on the Calculus AB exam. She then, went on to take Calculus BC as a senior. During high school, Simrat was a proud member of Mu Alpha Theta, the math honor society at her school. Through her involvement with Mu Alpha Theta, Simrat has had many experiences tutoring her peers. She loves working with students and kids to help them excel and prosper in math. Simrat is very excited to teach students and share her knowledge with others.


Shahnaaz Khader, Instructor

Shahnaaz Khader is a senior at John Champe High School and the Loudoun Academy of Science. She has received a perfect score on the math portion of the SAT, a perfect score on the Math 2 SAT subject test, a perfect score on the math portion of the ACT, and a 5 on the AP Calculus BC exam (the highest score possible). As captain of policy debate club and secretary-general of the Model United Nations club at her school, she loves teaching fellow students and helping them find their interests. Shahnaaz is excited to further her love of teaching and math as an instructor at Mathnasium.


Landon Labuskes, Instructor

 Landon is salutatorian of the Class of 2017 at Paul VI Catholic High School and will be attending the University of California at Berkeley in the fall. He has received a perfect score on the Math 2 SAT, a 5 on the AP Calculus BC exam, and was one of only 12 perfect scores in the world on the AP Calculus AB exam - as a sophomore. Additionally, he was a National Merit Finalist and attended the Virginia Governor's School for Math, Science, and Technology. Beyond his accomplishments as a student, Landon has a passion for sharing knowledge with others, serving as a tutor through the National Honor Society and the Latin Honor Society.

Jessica Ly, Instructor

Jessica is currently a senior at Thomas Jefferson High School for Science and Technology. She is taking BC Calculus and earned a 5 on the AB Calculus Exam and a near perfect score of 750 on the PSAT math section. As an officer of the Women in Science and Engineering club at her school, she has a passion for inspiring and exploring a love for STEM in her peers. In her free time, Jessica enjoys running, baking, and hiking.

Lloyd Mebane, Instructor

Lloyd holds a Bachelors degree in Computer and Systems Engineering from Rensselaer Polytechnic Institute and a Masters degree in Systems Engineering from George Washington University. He has spent his entire professional career working in engineering, but has tutored STEM related subjects since he was in high school. Lloyd believes that math teaches a person how to take large problems and break them into smaller problems which is a skill that is useful for all walks of life. A skill that he enjoys sharing and strengthening in the students that come through our doors.

Kristy Shin, Instructor

Kristy Shin is pursuing an Industrial Engineering Degree at the University of Illinois at Urbana Champaign. While at Thomas Jefferson High School for Science and Technology, she completed Multivariable Calculus. Her teaching experience began in her junior year in high school, teaching students from Algebra 1 to Calculus AB. She has a passion in tutoring math, and her goal is to help every student be more confident in math.





Rebecca Summers, Instructor

Rebecca Summers has a passion for teaching and has taught in Loudoun County Public Schools for over 10 years.  She is currently a Special Education teacher at the elementary level. She is completing her masters in special education at George Mason University.  Over the years, she has organized STEM summer camps, privately tutored individuals and small groups, started homework programs,  taught and tutored during LCPS' summer school.  As a parent of two now young adults who attended and graduated from Loudoun schools, she has parental/teacher experience with the sometimes fast-paced math curriculum. 

Rebecca has taught students  K-5 and believes that each student learns by various means and rates and she appreciates that Mathnasium shares that belief and individualizes each student's learning plan to meet their needs.   She admits that she often uses Mathnasium's instructional strategies in her classroom with much success.