Our Team
Devon Rossler
Devon Rossler is the Owner and Founder of Devon Rossler Tutoring. She has 20 years of continuous advancement and expertise in education. Devon taught elementary school in the Orinda Union and Walnut Creek Unified School Districts, in addition to facilitating and training teachers in all subject areas. She developed curriculum in math, reading, writing and grammar that is still being used in classrooms today. Devon is passionate about helping students grow academically, while also instilling confidence and self-esteem. She loves seeing her students’ growth and progress when working one on one and in small group settings. Devon always knew she wanted to be a teacher. Growing up she turned her basement into a classroom, and friends and family became her students. She loves to read and also enjoys traveling, hiking and playing tennis in her spare time.
Owner and Founder
Katie Sahm
Katie Sahm has worked as a Bay Area educator for the past 15 years. Katie taught fourth and fifth grades in the Orinda Unified School District, founded and managed a local summer camp, has mentored beginning teachers, and tutored countless students. Katie has her Masters in Education, an administrative credential, and was named one of Contra Costa County’s Teacher of the Year finalists for 2020. Katie serves as the Director of Operations for Devon Rossler Tutoring. She works closely with Devon and all of the tutors to ensure students have a meaningful and productive educational experience. She loves doing yoga, reading, and spending time with her husband and two young sons.
Director of Operations
Paula Rathert
A Bay Area native through and through, Paula Rathert brings over 35 years of teaching experience in Walnut Creek, with a career dedicated to the foundational years of Grades K–2, where she has helped young learners build confidence in the classroom. With a specialized background as a Reading Specialist, she focuses on developing strong literacy skills while also supporting students in writing and mathematics. Paula is passionate about working one-on-one with children to bridge learning gaps, help them reach their full potential during these critical early years, and make the process fun. Education is truly a family affair for her—both of her children have followed in her footsteps and hold teaching credentials. Outside of tutoring, she enjoys keeping up with sports, watching the latest Marvel movies, reading, and going on long walks.
Tutor- Grades PreK-3
Terry Pollack
Terry Pollack taught elementary school for 26 years before retiring from the Orinda Union School District in May 2023. She holds advanced degrees in educational leadership and has been a professor at San Jose State University. Terry continues to enjoy working directly with students to help them achieve their learning goals and potential. Terry also enjoys quilting, hiking, reading, visiting her son in Washington DC, and spending time with her husband and border collie, Ziggy.
Tutor- Grades 2-5
Jami Mackey
Tutor- Grades K-8: all subjects, 9-12: ELA & Executive functioning
Jami Mackey is a Bay Area native. She graduated with a BA in Interdisciplinary Studies and MS in Curriculum & Instruction. She has a passion for learning and has been working in education for more than seven years. She has experience working with students in preschool to twelfth grade. She believes in making learning fun and engaging for students. Math and reading were her favorite subjects as a student. Jami enjoys working 1:1 with students, because she can provide personalized learning and students have the time and attention they need to flourish. A fun fact about Jami is that she volunteered in Romania for a month working with children in foster homes and hospitals, engaging children in play-based therapy. Jami and her husband have a son and a daughter who keep them very busy! They love going on day trips, reading, engaging in art, and cooking in their free time.
Marci Winer
Marci Winer is an experienced educator with over 15 years in the classroom. She currently teaches 5th–7th grade math at a private K–8 school in Lafayette, and has also taught 4th grade math as well as 5th and 6th grade science. Prior to this role, Marci spent seven years at Springhill Elementary School, where she taught physical education and supported students across all grade levels in the classroom. Marci is passionate about helping students build confidence and find success in math. Outside of teaching, she enjoys staying active and spending time with family and friends. She and her husband raised three boys in Walnut Creek, and recently celebrated their youngest graduating from college.
Tutor- Math Grades K-8
Tom Sheridan
A beloved DRT tutor from his time living and teaching in the Bay Area, Tom Sheridan currently lives in Columbia, Missouri, where he teaches Special Education and coaches women’s tennis at Battle High School. He continues to see students in grades 3–8 virtually. Born and raised in St. Louis, Missouri, Tom received his Bachelor's degree in K–12 Special Education from the University of Missouri-Columbia in 2012. He has since taught in special education and general education classrooms in the USA and the UK across public, private, Catholic, and charter schools. Tom’s motivation to see his students succeed, grow, and become independent thinkers drives him to craft learning opportunities specific to his students’ learning styles. He focuses on building relationships with students and challenging them in their thinking to push them to their greatest potential. In his free time, Tom enjoys playing music, tennis, hockey, golf, and pickleball, and loves to hike and stay active.
Tutor- Grades K-8
Tina Zwahlen
Tina Zwahlen is a passionate and experienced educator with a teaching degree from Brigham Young University. With a wealth of experience teaching in various states, she has worked in 1st, 2nd, and 4th grade classrooms. 16 years ago, Tina settled in Orinda, where her 4 children attended local schools. Currently, she works as a Literacy Specialist in the Moraga School District where she continues supporting students in their reading and language development. In her spare time, Tina loves traveling, spending time with her family, and is a devoted college sports fan.
Tutor- Grades PreK-4
Tutor- Upper Elementary and Middle School Math (all courses), Algebra 1, Algebra 2, Geometry, Trigonometry, Pre-Calculus, Calculus
Clare Letendre
Clare Letendre recently graduated from Saint Mary's College of California with a degree in Mathematics and is now pursuing her Master's degree and single-subject mathematics teaching credential. Originally from Philadelphia, Pennsylvania, she moved to California to pursue her dream of becoming a math teacher. Over the years, Clare has served as a STEM tutor, peer mentor, and calculus teaching assistant, and she further developed her teaching skills through the Memphis Teaching Residency Fellowship. Having once struggled with math herself, Clare understands that every student learns differently and enjoys adapting her teaching approach to help students build both confidence and understanding. She is passionate about empowering students to reach their full potential and finds great joy in watching them succeed. In her free time, Clare enjoys crocheting, reading, and painting.
Maya Hoffstadt
Tutor-Upper Elementary and Middle School Math (all courses), Algebra 1, Algebra 2, Geometry, Probability & Statistics, Environmental Sciences, Spanish 1 and 2
Office Manager
Maya Hoffstadt is a recent graduate from UC Santa Barbara with a degree in Statistics and Data Science. She is pursing her single-subject mathematics teaching credential and is passionate about helping students succeed in math with the goal of making math approachable for every student. Having experienced both struggling with math and later becoming someone classmates turned to for help, she understands that every student learns differently and enjoys finding approaches that help math click while building confidence along the way. She has spent several years working with students as a swim instructor and camp counselor while also mentoring first-year students as an officer of her collegiate triathlon team. Maya enjoys biking, swimming, and spending time with her dog.
Tutor- Elementary and Middle School Math (all courses), Middle School Science, Algebra 1, Algebra 2, Geometry, Probability and Statistics, High School Science (all courses), Middle and High School: General Curriculum Support
Maggie Cove
Maggie Colton Cove is a PhD candidate at the University of California, San Francisco, where she studies how brain tumors interact with the immune system. In addition to her research, she is also an adjunct lab instructor at the University of San Francisco, teaching molecular biology and genetics. Maggie is passionate about STEM education and making complex topics more approachable and engaging at every level. With years of teaching experience, she is skilled at adjusting her approach to accommodate different learning styles. Outside of lab (and the dissertation she's racing to finish this year), she's usually doing yoga or getting bossed around by her three cats.
Tutor- Middle School Science, Middle School Math (all courses), High School Science (all courses), Algebra 1, Algebra 2, Geometry, Trigonometry, Pre-Calculus, Probability and Statistics, Spanish 1 and 2 High School: General Curriculum Support
Madison Bailey
Madison Bailey received her undergraduate degree in Biology and is on the single-subject teaching pathway at Saint Mary's College of California. Originally from Southern California, she is dedicated to making learning accessible and engaging for all students. Madison gained valuable experience as a college-level biology lab TA, where she enjoyed supporting students as they navigated complex biological concepts. As a former college athlete, she developed a strong sense of discipline and teamwork. In her previous role as a mentor with Big Brothers Big Sisters, she empowered young girls to build confidence and embrace their potential. Madison believes in the importance of inspiring curiosity and self-assurance in her students. In her free time, she enjoys reading, working out, and trying new recipes.
Anne Chalmers
Anne Chalmers works in the Lafayette Elementary School District as a special education teacher. Before teaching she worked as a journalist and received her Masters in Journalism from the University of California, Berkeley. She feels helping students build their confidence is a major component of academic growth, and she bring patience, care, and intention to her work. Anne is a lifelong writer and reader and is passionate about helping kids build their literacy skills.
Tutor- Grades K-5
Tutor- Upper Elementary and Middle School Math (all courses), Algebra 1, Algebra 2, Geometry, Trigonometry, Pre-Calculus, Calculus, Probability and Statistics, Computer Science
Preston Vo
Preston Vo graduated from Las Positas College with Associate’s degrees in mathematics, physics, and computer science, and he is now a transfer student at UC Berkeley pursuing a BA in applied mathematics. As someone who originally intended to not attend college at all, he understands firsthand the experiences of students who struggle to stay academically motivated and see the big picture. For Preston, education is more than just getting a good grade; education is what makes us better people. Having tutored for many years, he has helped a variety of students achieve their goals and learn to enjoy learning. When Preston is not studying, you may find him playing piano, composing music, weightlifting, or spending quality time with friends.
Gena Bullio
Gena Bullio is a current college student majoring in philosophy with a passion for guiding students through the writing process. Whether working on analytical essays, personal narratives, or research papers, she excels at helping students organize their thoughts, develop strong arguments, and refine their writing for clarity and impact. Gena’s tutoring style is thoughtful and encouraging, fostering a welcoming and productive space where learners feel supported and motivated.Beyond academics, Gena serves as the leader of her school’s Wealth Management Club. There, she demonstrates initiative and leadership by mentoring peers in career development and financial literacy—skills she believes are essential for long-term success. In her free time, Gena enjoys reading, writing, and hiking the trails around the Bay Area, always seeking inspiration in both nature and ideas.
Tutor- ELA Grades 3-12