Sheldahl Tutoring • Hundreds of Testimonials and Prominent Named Verifications

Private Math Tutoring • Grades 7-12

Algebra • Geometry • Trigonometry • Precalculus • Calculus

This collection of hundreds of parent and student testimonials along with prominent named endorsements is a tribute to all my tutoring students over the decades. It’s about the intellectual journeys we have taken together, your love for learning, your hard work and perseverance, and your achievement of educational excellence. Congratulations to every one of you; approbation with distinction and well done!

Dr. George
Harvard Ph.D.
MIT B.S.
Perdocere Inc.
phone: 833-MATH-833


Prominent Endorsements

✏️ From:
Marlyn E. McGrath
Director of Admissions
Harvard University

“I think George is not merely a tutor – he is a real educator. He knows that what helps students perform well on tests is the same as what makes them good students. A solid academic foundation pays dividends throughout schooling and careers, and George never loses sight of that in his work.”

Perdocere Tutoring - Prominent Named Verifications

✏️ From:
Prof. William A. Goddard III
California Institute of Technology
(Caltech)

“I have known George for decades. He has a very clear and dramatic effect enabling students to think and rise to their full potential. George’s influence on so many lives has had significant impact, and I greatly admire him for doing this.”

Perdocere Tutoring - Hundreds of Parent and Student Testimonials

Parent and Student Testimonials

✏️ “George taught me the difference between wisdom and knowledge, and George is by far the most experienced and intelligent teacher I have had the pleasure of working with.” (800 Math SAT, 800 SAT Math IIC, 36 ACT)

✏️ “George is a great tutor and is a great person to work with and not only has helped me learn, but also improve the quality of my work and has helped me change my style of doing math into an easier and more comprehensible method.”

✏️ “I am happy to have George as my daughter’s tutor. He is thorough and organized and has helped my daughter understand the subject better. I am pleased with my daughter’s improved performance in her school quizzes and tests. I highly recommend George.”

✏️ “Believe it. It’s true. Before George started tutoring our daughter, I read every single one of the testimonials on this website. It was clear the students and families were overwhelmingly pleased, but could he teach our child? It took mere minutes before I heard our daughter say, "Oh I get it! That’s easy" At that very moment, two things happened. I quietly breathed a sigh of relief because I knew we had found the perfect tutor, and our daughter began to believe in herself. The big question in our house a few months ago was “What are we going to do about math?” Now we’re looking far ahead and wondering to ourselves, “What will she do with math?” ”

✏️ “George knows his math. His educational accomplishments speak for themselves as does his many years of experience tutoring the subject. He has done a great job with my son. He has awakened his love of math. He simplifies where it is complex and enriches where it is too simple, balancing the subject and keeping my son engaged. This year my son has earned an A in math so obviously he gets results. More than that, George is a great person and my son truly looks forward to and enjoys his sessions. Working with George was one of the best decisions I ever made.”

✏️ “George is a very sound investment for parents seeking to help a struggling student. George genuinely cares about the teaching aspect of education and his concerns are focused on ensuring the student understands each concept thoroughly. He recognizes that while grades are the formal measurement of results, just as important is the student’s confidence level and comfort with the subject matter. As a consequence, our daughter’s grade rose from a C- to an A- in two months, but equally satisfying is seeing her growing confidence in herself and her abilities.”

✏️ “I don’t know how I would get through high school without you.”

✏️ “The best tutor we have ever had, and the nicest!”

✏️ "George’s help in my precalculus math course was outstanding. George understood that junior year is an incredibly busy year, and he wasted no time in explaining the information to me and finding the best way to convey the message. When I felt that something was too hard to understand, he would find a new way of explaining it. George always tries to make things easier to understand, but is also concerned that I perform to my best ability. George was prepared for everything that was coming in my course, and therefore I had a great advantage in the class. I’m grateful that I not only succeeded in math, but I also had a tutor that cared just as much as I did that I succeeded.”

✏️ “The first time I took an SAT math practice test, I scored a 540. I was confident in my math skills, but I still scored quite low. After learning with George, I realized that my problem solving skills were not refined. George taught me how to think. The SAT math section does not actually have any extremely difficult math. The real tough part is solving a problem efficiently and accurately. George taught me how to connect many topics of math together to do this. By the time I was ready to take the real SAT, I was scoring 800’s on the practice tests.” (800 Math SAT)

✏️ “George has been a helpful, effective tutor whom I would recommend to most anyone. He quickly shows you everything there is to know about SAT math and installs it into your memory. Furthermore he is a nice guy who genuinely wants you to improve.”

✏️ “Before I began working with George, I was getting good grades in math but much of the time I didn’t really understand what I was doing or why I was doing it. After my first session with George, I could tell he was a different kind of teacher. He really explained the concepts instead of just teaching me steps that I had to memorize. George always makes sure that I completely understand what I am working on before we move on to a new concept. I look forward to my sessions with George. George makes the sessions fun, interesting, and challenges me to think in ways that I haven’t been taught in school. George also happens to be funny and kind and I feel he really cares about me as a student.” (96% Final Math Assessment)

✏️ “This year our son attended the Perdocere Math SAT Prep Course. George’s clear, well-presented explanations and thorough review of the SAT Math was very helpful. We finally found someone with a high-level math knowledge base and also with the unique and most important quality – the skill of teaching in a manner that is understandable. George has helped our son gain knowledge, skill and confidence.”

✏️ “Following a couple of years with disappointing math teachers, my son was struggling in his Algebra 2 course – and then the pandemic hit, and distance learning compounded his problems. At this point we reached out to George. George took the time to work back through the older material to build up a strong foundation for future success. The first few months were triage; even so, we noticed improvements in performance almost immediately. In addition to laying a strong mathematical foundation, George has done a great job teaching my son solid study habits and test-taking strategies. My son is comfortable with the material and confident that he will perform well on his tests. I am certain that my son is now on a trajectory that will guarantee success in math through the end of high school and beyond.”

✏️ “I’ve been a student of George’s now for four years going on five. I tried other tutors but no one really does it quite as well as George. He does his best to help the student and to ensure their good performance. One night, before the SAT George stayed with me for roughly six hours to ensure that I got my 800 on the math portion of the SAT. Overall George is the best tutor I’ve had thus far, and if you are looking for honest results George is the way to go.”

✏️ “George is the best math teacher I have ever had the pleasure of working with. Before I met George I had a 670 on my math SAT, and now I am getting 800’s consistently. I owe it all to George because he is constantly pushing me to work hard to achieve my goals. He teaches me more than I need to know so that I understand all the math on a higher level. George has always supported me and has made me a better learner.” (800 SAT math)

✏️ “Anyone who says that the SAT Mathematics section cannot be taught has not met George. After scoring a low 600 on my first practice exam, George stepped me through the process of learning how to take the test as well as the mathematical concepts behind it. After several months of training, George helped me to receive a perfect 800 on the Math section. And if that wasn’t enough, he also guided me through the SAT Mathematics IIC Subject Test, which, with his aid, I scored another perfect 800. Thanks to George, I was able to conquer the SAT’s.”

✏️ “For the last two years, George has done everything he could to help me in both Algebra 2 and Honors Precalculus. My grades improved significantly in a very short period of time, and were maintained throughout the school year thanks to him. He knows the material very well, he is extremely good at explaining it in simple terms, and above all, he is a very easy person to get along with. I highly recommend George as a tutor, not only for the effort and attention he put into preparing each of my lessons, but also because I know he invests that same effort and attention in every lesson he gives.”

✏️ “He has genuine passion for teaching in its most basic sense. His subject knowledge and teaching style encourages our child’s participation in a planned roadmap for success.”

✏️ “What would our schools be like is we could witness George’s way of teaching there? Quality, it works!”

✏️ “Who you gonna call?? We have relied on George for both of our daughters in tutoring Mathematics and Chemistry. I noticed George’s ads, called him and the rest is history. For my older daughter, we began seeing George in the second half of her junior year. She needed a quick review for her upcoming SAT, after having scored in the 600’s for her PSAT. She received a 730 on her first try. In addition, my daughter was struggling in her Precalculus course, despite studying under a different tutor earlier in the year. George salvaged my daughter’s junior year math grade, and she ended the year with an A-, after a rocky first half. He takes a very methodical approach to teaching, and doesn’t believe in shortcuts. To excel, the student must understand the concepts, and not simply memorize rules. We called on George again to help my daughter through her senior year Calculus BC course, as well as to tutor her for the retest of the SATs, for the Math II exam and for her AP exam in BC Calculus. Needless to say, the results were stellar. She improved her SAT math score to a 780; received a 790 on her Math IIC exam; eeked out an A- in her BC Calculus course for the year, and topped it off with a 5 on her AP BC Calculus exam. She was thrilled particularly with the AP score, because it satisfied her Math requirement in college. But guess what? She may become a Computer Sciences major, and is probably going to have to take a lot more math. And she can approach college math with confidence, given the solid foundation George provided her. My younger daughter is a junior in high school and is taking AP Chemistry. She loves the subject, but was finding the subject matter increasingly challenging during the fall semester. We called George, he taught her for three sessions and she was thrilled to get an A on her mid-term, and an A for the fall semester. She was impressed with his thorough understanding not only of the subject matter, but of how the teacher required questions to be answered. He discerned that the teacher required responses that exactly followed the AP test… my daughter adjusted her answers accordingly. I think we are going to have to call on George again soon…the material is becoming challenging again, significantly more difficult than the questions on the Chemistry AP exam, and we take comfort in knowing he has complete mastery of the material and boy, does he know how to teach! — A happy parent.”

✏️ “George is the best math teacher I have ever had and for the first time in my life I can now say I feel confident in math. I get it! He is so organized. He challenged me to really push the limit and had confidence in me that I could achieve the goals we set together. I wasn’t to sure but with his methods, encouragement and great teaching I did it and feel great about it too. I did greats on my SATs, my math grade is an A and I now will enter the honors level. I wish I had met George earlier. Thanks George.”

✏️ “Our daughter would have never gotten accepted to the highly selective college she now attends without George. Meaning she would have missed the opportunity to go to the school that’s turned out to be perfect for her. We thank our lucky stars for George every single day.”

✏️ “George started late in the year tutoring our son, in a very short time his grades were up. His scores on the SAT and AP exams were exceptional. However what is more important is that George is coaching him on how to study and not only tutoring him in a subject. He is helping him choose his courses, as well as guiding him through his high school years. The look on both their eyes while studying is one of pure joy. George is an exceptional tutor as well as a dear friend.”

✏️ “George was flexible and accommodating when my daughter and I found ourselves overscheduled one month before three scheduled SAT-2 examinations. He organized a study program, identified the appropriate tools, and worked out a mutually acceptable schedule on short notice. His thorough understanding of the information and the test process coupled with his kind and cheerful personal style was very effective. The outcomes met our very high expectations, and we look forward to working with him in the future.”

✏️ “Thank you for your excellent help during our daughter’s absence from school. She returned not missing a beat in Trig and Chemistry. Not only that, your joy in teaching the material and encouragement further increased her interest in both subjects and boosted her confidence. We hope you will be able to continue working with her – it is such a pleasure to watch a child bloom academically!”

✏️ “A word of advice: start with George early. Building the proper foundation in math is crucial to getting good grades in all years of high school as well as good SAT math scores.”

✏️ “George is a godsend. He breaks math down in a language students understand while making the process enjoyable. By laying out the mechanics of math, he lays down a foundation for comprehension the student carries forward throughout their academic career. He also gets results. My son quickly grasped the concepts and went from a C+/B- student to an A student. He also moved up two class levels in his math placement. His improvement correlated directly with his confidence, which soared. He now thinks of himself as the math guy. The greatest compliment is that I recently asked him what he wants to be when he grows up and he said a math teacher.”

✏️ “Frustrated by the lack of tangible Math achievement in my children, who are good students, through their middle and early high school years and with one facing the SATs in the spring I needed to act fast… I decided to tutor them. After trying a few tutors where the fit was never quite right I stumbled on to Perdocere and from day one my problem was solved! George understood completely what I wanted: to improve their math school work, prepare for their SATs, but also to make sure that they knew MATH. I asked George to make sure that all his math tutoring would stick; I didn’t want them to ‘just learn it for the test’. His success is tangible. They have great grades and success with the SAT. One of them said to me ‘Mom I learned more in four hours with George than I did all year in my math class!’ ”

✏️ “Every time I see George with my son, I feel very happy and blessed knowing that he is in good hands. My wish is not just for my son to raise the points or grades but also to learn what “study” truly means through Math so that he can apply the concepts and skills across the fields in his lifetime. George is a teacher and mentor who can make my wish come true.”

✏️ “George is not an ordinary math teacher. Not only did my son receive phenomenal math tutoring, but George also boosted his confidence. I’d overhear George encouraging my son, ‘Let’s look at the problem carefully, it’s easy…’ By upping my son’s self esteem, George was able to improve his score. George also built up my son’s stamina by having him take full length practice tests so he’d be prepared for the actual SAT.”

✏️ “George not only taught me math and chemistry, but taught me in a way that was practical and easy. Compared to school teachers, George actually explains things in a simple way and most importantly taught me how to think through any problem, which is by far the most valuable lesson I have learned from him.”

✏️ “George made it possible for my son to go to the best college for him. George is the best teacher and mentor my son could have. We cannot thank him enough. I cannot wait to see my other children grow as learners with knowledge and strategies taught by George.”

✏️ “George taught me a new way of thinking. He retrained my brain to think the way he does. I never have to memorize formulas, or remember a certain method. George taught me how to analyze the core math behind a problem, and derive how to solve it on the spot. It is a skill that has paid off incredibly. Thank you George!!”

✏️ “Our middle school son has a broader, deeper understanding of math concepts since working with George. He no longer memorizes formulas without knowing the why’s and how’s of problem solving. George can teach tough math concepts in an understandable way that translates into learning!! The success our son feels in mastering the math is a great boost to his self esteem. He just got an A+ for the year in eighth grade algebra.”

✏️ “It is with both pleasure and sadness that I write this testimonial for George who has tutored my three children over the last five years in a wide range of subjects (math, pre-calculus, chemistry, physics, biology, computer science, and a little engineering on occasion). George has been an extraordinary resource and has become an honorary family member and a dear friend to me and all my children. He has seen my children through quizzes and tests, helped with tricky homework assignments, and led them to superlative performances on their SATs, APs and ACTs. George has been a terrific mentor as well as a tutor, giving advice on school, the college application process, and the like. George keeps up to date with all assignments posted by the school and helps even disorganized kids get organized. He is terrific at reminding the kids of deadlines for projects, assignments, quizzes and standardized tests. He has always made time in his busy schedule for extra sessions when a big test or project is due, he explains why and how rather than tell a student just to apply the formula, he adjusts his method and style of tutoring to each individual child, he is reliable and efficient and always pleasant, and his range of subject matter knowledge is superb. I honestly believe that George’s tutoring has had a big and most positive impact on my children in many ways. On the most obvious level, he truly did help boost their test scores and probably did impact the level of college to which they were admitted. Beyond that, however, he really gave them a greater appreciation and understanding of subject matters that they were not as comfortable with, and gave them the tools to help them think, analyze and solve. These are tools that they will carry with them and use all their lives, whether they ever take another math course or not. That is what a real tutor does not just get you through the next exam. And even further, George honestly cares about his students not just their performance but also their minds, their interests, and their character. Whenever my two oldest are home from college, they are delighted to see George again, and I know that my youngest will miss George when he starts college this year, as will I. George has been a big part of our lives. We are better of for the experience in many, many ways. Thank you, George.”

✏️ “We are ecstatic about the progress George has made with our daughter’s math scores. He has instilled possibility when she knew only defeat. The experience of success in math has given her tremendous confidence. Higher math had been out of her reach, but now it is easily grasped. George’s knowledge is boundless, not only in math, but also in knowing how and when to motivate psychologically and emotionally. He is always prepared and upbeat and he keeps each session moving enthusiastically. Our hope was that George would just give our daughter the ‘jump start’ she needed, but in fact, he has become a part of our lives for years.”

✏️ “I don’t know how we came this far without George. There has been a tremendous improvement in our son’s work. He has the A’s to prove it. George is truly a gem.”

✏️ “George has not just taught me, but he re-wired my brain in a way that allows me to comprehend subjects I haven’t gone over with him. He has given me the tools to understand any math or science problem out there.”

✏️ “Thank you for all that you do for our son!”

✏️ “Before working with George, I thought of math as a drudgery. The subject required a lot of work and study, but it seemed to me that no matter how hard I applied myself, I could not affect a change in my grade. Math was a chore and an ugly spot on my report card. After being taught by George, however, that all changed. George takes the time to explain the mechanics behind a formula, never allowing memorization where there is understanding to be had. Under George’s tutelage, I began to see the beauty of mathematics, and as my interest in the subject grew, I found myself considering it less a boring necessity, but a more rewarding challenge. George’s teaching has turned my opinion of math completely on its head, and also yielded pleasant results during the final exam. Although my term grades before meeting George were not fantastic, I was able to score highly enough on my final exam to bring my overall math grade up to an A-. Without George’s careful guidance, this certainly would not have been possible. I cannot recommend his services highly enough – under George, not only my grades, but also my outlook on math changed for the better.”

✏️ “George tutored our daughter for almost a year. He is a one of a kind teacher because he is so good as what he does. Our daughter said that George was able to teach her math concepts in such a way that she really understood the topics. Prior to George she was able to get through Algebra and Geometry courses with good grades but without understanding the material. George is very dedicated, very enthusiastic and really knows how to teach for understanding. He is also patient and positive and was good for my daughter’s confidence. She liked him very much which is always important too. I am not a fan of today ‘s highly pressured academic rat race, and I believe children are suffering mentally and physically. However, having a good tutor can really help certain students to succeed rather than just stumble through.” (U.S. exchange student, online tutoring, Viterbo, Italy)

✏️ “George has worked with our boy for the past eighteen months. The improvement in his grades, as well as his overall approach to school work has been amazing. His own words sum it up ‘George taught me a new way of thinking. He retrained my brain to think the way he does’.”

✏️ “We have had many tutors in the past and George by comparison is extraordinary. George’s weekly sessions helped my high school boys achieve never before A’s in their math classes. My husband and I were so impressed with his intelligence, dedication and patience. These qualities allowed my boys to truly understand SAT test taking and math strategies. We highly recommend George!”

✏️ “George’s capabilities extend well through college topics. After taking BC calculus my senior year of high school, I took a semester off before taking Calculus III in the spring term. What began as a speed review of single-variable calculus expanded to encompass numerous topics neglected in the high school curriculum, as well as proper explanations and proofs of many other topics. George’s first goal is to establish a solid mathematical foundation; or in a case like mine, backfill the incomplete foundation. From there, working into sciences or high level math becomes far easier.” (800 SAT Math)

✏️ “George has tutored my daughter in Pre-Calculus and Math SAT prep for the past year. George has very impressive credentials, but even more impressive is the math rapport he has with my daughter. Clearly, George understands math at a depth and breadth that few of us do. But his ability to teach it and be a successful tutor is really what impresses me the most. He is a natural teacher. He can see when a student isn’t “getting it” and he can explain a concept in a variety of different ways instead of merely repeating the same explanation again and again. And finally, George truly seems to love his job. He appears to be genuinely happy when my daughter accomplishes her goals or nails down a difficult concept. My daughter feels her time with George is always productive as he’s always prepared for their session.”

✏️ “I’m in honors math. However, I couldn’t handle Algebra-II as well as Honors Geometry. So my grade began to slip so my parents called George. It was the best decision. George knows everything about math and he was able to guide me through the daunting path of Algebra-II and Trigonometry. He made everything less intimidating, and within no time, my grade was back up. George is definitely going to be my tutor next year.”

✏️ “Thanks again for everything you have done for the boys – you really have a gift!!”

✏️ “I’ve always struggled with pre-calculus and calculus. My teachers never taught the theory behind the problems, or how it was connected to the big picture. George makes it his mission to make sure you thoroughly understand the concepts of the subject.” (college calculus student)

✏️ “I used to hate math and everything to do with it. But now that I’ve been working with George and I am ahead in my work, I absolutely love math now. I can’t even tell you the satisfaction I get when I know all the math in class the first time the teacher tells us. Also, my grades couldn’t be better right now, and it is all due to George”

Click Here for the Complete List of Hundreds of Parent and Student Testimonials. What’s Shown Above is a Small Sampling.