Callahan Math Tutoring • Hundreds of Testimonials and Esteemed 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

✏️ “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 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.”

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

✏️ “We simply could not ask for a better qualified, kind and sincere educator for our son.”

✏️ “We would heap praises, but facts speak better. With a ‘C’ in 8th grade math, and teachers happy with ‘the C’, which translates to just passing 8th grade MCAS at the cut-off grade, we looked to George to teach our child. The weekly two-hour session is productive and fun for our child! We would never have imagined our child sitting for two hours on High School Algebra – but it happens every week – only with George. George finds a way to teach and convey concepts in math – overcoming our child’s learning disabilities. Our child brought home a B+ in Algebra, and in one Algebra quiz, got the first time ever 100%. Our child has gained confidence which beats the frustration and ‘I hate math’ during 8th grade.”

✏️ “Working with George has improved my math skills immeasurably. I was able to achieve a near perfect score on my Math SAT as a result of George’s dedication, patience, and skill in our tutoring sessions. He made sure I not only understood the concepts but had a deep knowledge of them. I also worked on my school work with George and felt that our work together put me well ahead of my fellow students.” (790 SAT Math)

✏️ “George has been working with my son since June. When I called George we had a great conversation and I explained the math issue my son was having. He understood the issues and had a solution and a game plan to attack the problem. Since working with George my son’s math comprehension and retention has improved. But more importantly, my son looks forward to working with George weekly and requires no prompting to be prepared for tutoring. He uses positive reinforcement to engage my son. Currently, George is working with my son on SAT preparation. The strategies put in place will allow my son to do well on the SAT exam.”

✏️ “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)

✏️ “Although I’ve only been with George for a short while, the most important thing I have discovered about him is that his teaching style is highly effective. Not only does he teach you how to do something, he teaches you why it is done that way. He is able to show you how basic concepts can be used to solve highly complex problems. Now, I am able to see the building blocks of each individual problem, and, from there, I am able to find the solution. He is totally approachable and will help you with anything. I know on countless occasions he has also given me advice that I find applicable to my physics homework. He truly does instruct his students very thoroughly, and if you are unsure of something, he will go over it as many times as you need. Because of him, I feel thoroughly prepared to take my SAT exam.” (700 SAT Math)

✏️ “George was a wonderful tutor for my daughter’s Math SAT prep. George has a complete understanding of the Math SAT test. He is also skilled in teaching high school students this information. We were thrilled with the results! A very satisfied mom.” (730 SAT Math)

✏️ “Whether in a group or individually George is by far the best tutor I have had. His knowledge is extensive and he teaches in a way that complex subjects are easy to understand. I’ve used other tutors and centers and none compare to George. He is such a great teacher that I kept bugging him to teach at my high school.”

✏️ “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.”

✏️ “George has been the best investment we could have made for our son. He has been tutoring him for over two years now and our son has been in honors math ever since. He and George are now in the process of SAT ‘training’, if you will. We just know that his scores will be nothing but impressive. Thank you, George.”

✏️ “George has been tutoring me for eight months. While he has a relaxed personality, he thoroughly explains all important concepts and makes sure that I full understand the topics before moving on. His knowledge is vast and I really enjoy working with him.”

✏️ “When George takes on a student, for him it is not just a job, for him it is a commitment which he honors spectacularly. A commitment to help you do well in school and also a commitment to actually learn the subject matter.”

✏️ “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 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.”

✏️ “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.”

✏️ “We just keep coming back for more! George has been working with at least one of our children for the past five years. He has firmly grounded them in mathematics and physics and has given them the confidence to handle any problem set that is assigned. Perfect or nearly-prefect SAT and SAT-II scores have also come the children’s way during this time – and George can truly take credit for readying them for these standardized tests. He knows that strength in fundamentals and hard work are the most important variables in the success equation. George is an educator first and foremost. He explains concepts in a clear and concise manner and has a way of consistently reinforcing these concepts. He pushes his students to achieve… but always in an extremely supportive manner. George does what is necessary to ensure that his students understand what is being taught. He wants all of his students to succeed – and is truly vested in their success. In sum, we can’t say enough good things about George… now if only we could clone George for the SAT critical reading.”

✏️ “George has been tutoring our son for four years, and we are extremely pleased with the results. George has taught our son the way he needs to be taught to, he is positive, thorough and focused. Our son has a confidence in his abilities he could’ve only imagined before. George not only teaches, he mentors and advises, he truly cares about his students and their accomplishments. We highly recommend George, he will not disappoint!”

✏️ “Before I started working with George, I lacked the confidence and tools to complete my math year with a strong ending. After just three meetings with him I began to receive A’s rather than C’s. Not only does George teach with passion, but he also tailors his explanations and the presentation of the material to fit my specific needs. His commitment to my learning is exemplified by willingness and ability to describe the real content and meaning of the work rather than simply relying on the memorization of formulas. Working with George has made me believe that the key to successful learning is dependent on a great teacher – and George is a great teacher.”

✏️ “Perdocere Math Tutoring with Dr. George was the best decision we ever made for our son. George has not only given our son the knowledge and understanding of math, but the confidence to master it. He has given him the skills and confidence he needs to truly be a success. We can thank him for not only the math skills learned but also his advice in SAT management and preparedness and in interview techniques. We give Dr. George a perfect score!”

✏️ “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.”

✏️ “He is very patient and explains complex terms in simple English. He also works hard to keep a smile on your face even when things are difficult.”

✏️ “George is a fun guy who knows his stuff. He is enjoyable to work with and the results are astounding.”

✏️ “Far more than a brilliant teacher, George’s warm and positive attitude has been truly therapeutic by giving our daughter a new confidence and competence in math.”

✏️ “George’s results have been spectacular in terms of overall grasp of subjects and preparation for specific exams. He is the cause of one or more of our children getting perfect or nearly perfect scores on SAT or AP tests where, in some instances, the effort was there but, prior to George, not much interest or aptitude a specific subject. He visibly changes good students into superlative students.”

✏️ “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.”

✏️ “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.”

✏️ “George is the real deal. Not only does he have a stellar educational background and a wealth of experience, but he has the tutorial skills to impart various math concepts and a real gift for connecting with students. My son has happily worked with George for five years; during that time, he consistently has brought home A’s. Simply put, George is the best there is.”

✏️ “George has a superior understanding of higher mathematics and science which combined with his ability to communicate abstract subject matter to the kids is like no other teacher we have known. As for results, George has guided our son from mediocre to excelling. His high MCAS scores are a measure of his dramatic improvement. His SAT practice scores steadily climbed to impressive levels, and he gained 240 points on the SAT math. George mentors and provides guidance with understanding to his students. Our son has developed a strong sense of purpose to do well which we attribute in part, to his mentoring. We’ve had George tutor both our sons. George is the best gift you can ever give to your son or daughter.”

✏️ “George is a brilliant mathematician who has the rare ability to convey that knowledge to our teenagers. He is an effective communicator who teaches with patience, determination and perseverance. George understands that confidence is the most important ingredient for learning and empowers our children to believe in themselves.”

✏️ “George is an amazing teacher. He is the best tutor a parent can hire to help their child succeed in both mathematics and science. George is true to his thorough teaching; he goes beyond the knowledge taught at school to explain concepts. Having George as a tutor has been invaluable to me throughout high school. Whether you seek to improve grades in school, or simply to study advanced topics, no one can do a better job at helping you than George. George taught me basic calculus the summer before my AP Physics B course, which allowed me to view physics in a whole different perspective than the rest of my classmates, and has led me to decide to major in Biophysics next fall. And as I sit in my AP Calculus class this year, I can only smile and think, ‘George has taught me well.’ ”

✏️ “George is the best tutor that our family has ever used. No one else is even close. He quickly identified my son’s strengths and weaknesses, and then set about in an orderly, sensible and strategic way to fix the weaknesses. There was a purpose to every problem set or test that he assigned. George customized his approach to the individual child which in turn created ‘buy-in’ from my son, who realized that he was not going to be assigned busy work, but focused problems designed to address areas that needed work. Bottom line my son got a 55 on the PSAT math and 8 months later, with George’s help, got a 770 on the SAT math.”

✏️ “We are absolutely thrilled with what George has done with our son. He has instilled a sense of confidence, made him realize that he can excel academically and allowed him to set his sights on things that he never thought he could achieve. George is incredibly knowledgeable, extremely approachable and a fantastic teacher. He has gone out of his way to make sure that our son is always prepared for his next challenge. George will be part of our family’s academic life for years to come!!”

✏️ “George plainly has a mastery of math and science that runs both broad and deep, and he is very, very good at communicating with both students and parents in clear English pitched to their level of scientific understanding, wherever that may be. He clearly cares about his students, and we feel very confident that he is happy to help any way he can.”

✏️ “We felt like we struck gold shortly after George began to tutor our son toward the end of his junior year. The impact was almost immediate. He skill level went from a fail to pass in a few sessions. George has an expertise in communicating math and science surpassed by no one. He was able to identify and fill in the gaps in our sons math education in two-hour per week sessions when regular classes and after school failed. Our sons precalculus and calculus teachers were unable to communicate the subject matter in a way that our son could understand. Our son proclaimed that George was the best math teacher he ever had in his entire high school career. He had somebody who could explain abstract concepts in a way he could understand. George prepared our son for the SAT exam and continued tutoring our son during his senior year in high school for advanced math. Honors precalculus and calculus are hard enough subjects for anybody to grasp or master, but they are especially difficult when you have a learning disability. We have no reservation in giving George our highest recommendation.”

✏️ “After the first couple of math tests at the beginning of my sophomore year of high school, I knew I needed help. After just a couple of sessions with George I immediately became a standout in the classroom, consistently on the verge of a perfect test. George rebuilt the foundation of my mathematical skills, allowing me to see the ‘big’ picture and to intertwine new ideas with old concepts. His ability to aid me in understanding the undercurrents of what my teacher was lecturing on in school allowed me to excel in the classroom. I have had George as a tutor for three years and he has inspired a sense of appreciation in the workings of Mathematics that I am now considering pursuing the subject as a major in college.”

✏️ “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!”

✏️ “George is very involved in making sure our son is studying the material he needs to succeed and getting a clear understanding of what is expected of him. George takes time each week to prepare for our son as an individual. Our son enjoys the way George teaches him; it’s a great mix of teaching and really caring about the student. We know George was the right choice, our son went from failing to passing with an A.”

✏️ “Once your child has worked with George, you realize what an extraordinary teacher he truly is. George not only teaches in a professional and organized manner, he has instilled self-confidence in our son that goes beyond mathematics. Our son respects George not only for his ability to teach him, but also because he takes an interest in him personally. George not only gives careful consideration about what is being taught now, but what skills will be needed in the future. Our son took a higher level mathematics course this year than was recommended, and with George’s help he was very successful! He is a wonderful mentor, something we never expected! Thank you George!!!”

✏️ “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.”

✏️ “Over the past three years, George has become the family’s de facto math and science consiliari. He has not only guided our first son to a string of 800’s but instilled in him a sense of academic confidence and curiosity that will serve him well in college. He also started down the academic path with our second son this year – a very different learner than the first – yet he has struck the appropriate chords with him. George is a born teacher. He is enthusiastic about his subjects, explains and teaches in a clear and logical manner, and patiently drives the learning process. We can always count on George and will continue to rely on him in the future.”

✏️ “George has made such a big difference for our child – academically and personally.”

✏️ “In preparing for the SAT, George helped me dissect each problem into its basic parts. There is no better preparation for the Math SAT than with George.”

✏️ “Thanks to George I not only feel more confident in math, but I also feel like I am receiving a strong education from someone who is dedicated to helping people learn. Every lesson is based on what I need, and he never disappoints. His approach to math is both fun and engaging. He helps me get the results I want without substituting memorization for learning.”

✏️ “George gave our son the tools and confidence to achieve results above and beyond what he believed was possible. He is a terrific teacher.” (college student parents)

✏️ “George recreates the art of tutoring: he is like a muse who inspires learning as an art.”

✏️ “During junior year, Perdocere helped me prepare for several standardized tests in both math and science. Perdocere was distinctly more effective than the other tutoring organizations I tried. With Perdocere’s help, I earned a 740 on the math portion of the SAT I, a 760 on the SAT II Physics, and a 5 on the AP Physics B exam. George helped focus my hard work and succeed where I had to.”

✏️ “I have always struggled with math, but George has helped me conquer the beast.”

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