Online Math Tutor (Juan Castaneda, MS in Mathematics)




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The Multiplication Table

Factored Integers

The Circle


Dilations Around Points



Slope-Intercept Equation

Complex Numbers

Stirling Numbers

Numbers as Boolean Functions

Calculator TI-89

Tower of Hanoi

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Student Testimonials

Back in 2005 I started collecting testimonials from my students and from visitors to this site. I am grateful for my students' willingness to share their success.
I expect this page to grow and keep on growing. I would love the opportunity to help you with math and be able to earn your testimonial too!

"Dear Juan,
I wanted to take this opportunity to share some wonderful news. Blaze passed the ELM with a score of 52!
Blaze and I want to express our gratitude for your support, guidance, and tactical tutoring. I think that your help was critical in her success.
There were several colleagues who told me privately that her original score of 40 would be too much to overcome and that her next score would probably not be enough to make the benchmark.
I am so glad that Blaze and I decided to work with you, so that she could give the ELM another try, with a different tutoring approach. The results speak for themselves! She did it, with your help and guidance!
Thank you for your support and kindness!"
Dr. Jose R. - June 7, 2016

"Hi Juan,
Happy to tell you my son passed the ELM test and now I would like to see if you could help my daughter through the end of the year with Algebra 2. We would like to start next week if this is something that works for you.
Thank you."
Nina M. - May 15, 2016

"Hey Juan,
I've just finished with my Masters degree in Computer Science from Cal State San Marcos.
I'd like to thank you again for helping me out immensely with all my courses over the years."
Chad D. - March 15, 2015

"Hi Juan I ended up meeting my requirements in math on the GRE. Thanks for all your help!"
Anna F. - November 2, 2014

"Juan, [...] I got an A in the discrete math course and a B in the Linear Algebra course. Thank You for all your help!!"
Chad D. - June 28, 2013

"I just got back from Germany and I wanted to let you know that I passed my math exams and was offered a place at both of the Universities I applied :) I will be starting my semester at the European Business School in the fall. Thank you again for all your patience and endless hours of hard work spent with me! I could not have done it without you."
Julia L. - June 26, 2013

"Got A on the exam Juan thanks"
Phi T. - April 30, 2013

"Juan, I did it!!! I passed the class with a B!!! I am grateful for your patience and ability to explain math in a way that I could understand. Your help and guidance helped me gain confidence in myself and my abilities so that I could get through the course. I definitely recommend you to others that need help with math. I look forward to seeking your assistance in my next math course! Thanks."
Danielle C. - December 19, 2012

"I would like to let you know that I passed the CSET 1 I took last month. I am really thankful for all your help."
Francisco - August 18, 2012

"Juan, I got B in Calculus II !! Thank you."
Sarah A. - August 13, 2012

"Just wanted to touch base and let you know that I passed my final CSET exam (math/science). Thanks for your help Juan. I couldn't have passed without your help!"
Mason K. - July 30, 2012

"Hi Juan, thank you for all your help and patient guidance teaching Ben how to think through a problem mathematically-conceptually, and ultimately strengthening his mathematical know how in solving math problems successfully. Just to let you know Ben passed his ELM exam. As a result, his math confidence has greatly improved."
Debbie C. - July 14, 2012

"Hi Juan Carlos, You helped me through a crash-course self-study program to prepare me for the CSET Mathematics Subtests 1, 2, & 3. I passed all 3 tests (Alg/NumTheory after a 2nd try). You were a lifesaver with respect to getting past that hurdle and helping me remember 4 years of college math content, taken over a span of many years, in the most efficient, time-conscious way. I am very grateful for your willingness to go the extra mile."
Forrest M. - June 14, 2012

"Juan, I did pass the final!! I am just over the top excited and I did get a B in the class. Thank you so much for being such an amazing cheerleader, and tutor. You really helped me a lot, sharing with me your knowledge, and your love for math. I appreciate everything you did for me. You are really good at what you do, and I just want to say thank you, thank you, thank you ."
Shannon - May 25, 2012

"I wanted to tell you Alex raised her SAT math score by 120 points. This is a great improvement! Thank you for your help."
Maria M. - December 2, 2011

"Thank you Juan! I passed my water distribution exam. I got a 90%."
Viviana C. - October 30, 2011

"Hi Juan, I wanted to let you know that I did take the GRE and raised my math score by 120 points! [..] I'm happy! [..] Thank you for assisting me in raising my math GRE score."
Autumn M. - July 8, 2011

"I passed both of my CSET subtests. Thank you so much."
Kris H. - June 6, 2011

"I was exposed to calculus for the first time while in college and to be honest, I was lost. Not being math friendly to begin with, I realized that I needed help. After meeting with Juan for the first time, he noticed that I have "Math Anxiety." Before we started to work on any math problems, Juan cleared up my mind about math via a few tips and insights (and it worked!). As the tutoring sessions went on, my grade in calculus began to increase. Juan helped me understand the core concepts of calculus and why certain questions existed. In addition, he showed me the general approach to any math problem.
It was truly a pleasure learning from Juan. I guarantee you will be amazed by the vast amount of knowledge Juan has. As of today, I have no fear of math and I cannot say I'm "not math friendly." As for the college calculus class, I passed it with 88% (should have started tutoring sooner!). I will be making appointments for my GMAT preparation soon because my personal experience tells me, with Juan's help, I will pass it."
Fed K. - May 28, 2011

"Having only taken remedial calculus and statistics classes as a business major, I needed quick instruction to prepare for the TexES mathematics proficiency test to teach high school. This test is similar to the CSET mathematics tests, including stats, calculus, geometry, precalculus, number theory, and algebra. After four weeks of tutoring from the math tutor Juan, I was able to show my understanding of the material and passed the exam. He set a time table for me, gave me quick and thorough instruction, and clarified any question I had. He demonstrated usage of TI calculators, broke down the Chain rule, and even showed me the real world applications of integrals and other mathematical concepts. He is currently helping me with a Mathematical Modeling class. His range of knowledge is incredible, and he can be a source of aid to any finance, economic, chemistry, physics, math, statistics, applied math, engineering, or computer science major. If you need to get a good grade in a class, want to learn more about math, or just need homework help, then visit the affordable and highly competent math tutor Juan."
David P. - April 15, 2011

"I got an A in my Intermediate Algebra Class!!!! Thank you soooo much for your help!"
Lutheran C. - December 19, 2010

"I PASSED my trigonometry exam!! Thank you for your help Juan. You were very patient, very clear in your explanations and most importantly, listened to me when I was not understanding, even if I interrupted you. I just liked your calm and nurturing style, and it certainly paid off. I couldn't have done it without you since the instructor covers far too much material in far too little time. Thanks again!"
Monica D. - December 15, 2010

"As far as the GRE, all of your math tutoring helped me out immensely! I scored right around what I wanted to and don't think I could have done it without your tutoring. Problems were clear to understand because of the way you broke them down logically.
I have a new found appreciation for math because of your explanations for its applications throughout history. Thank you for your assistance, I truly appreciated it. If I have any friends looking for tutoring, I will definitely recommend you to them."
Sarah H. - November 5, 2010

"[..] I passed the algebra class! I never would have gotten through it without your help! Thank you for explaining math in a way I could understand so I can pursue my dreams."
Julie D. - August 25, 2010

"Hello Juan Carlos, [..] Thanks to your tremendous help and a much improved GRE math score (an increase of 140 points), I was accepted into the joint doctoral program at UCSD and SDSU."
Natalia E. - August 12, 2010

"I received an email this morning from Mesa College Admissions that I PASSED my math 141 Challenge Exam!"
Chad B. - June 18, 2010

"I just wanted to let you know that thanks to your help [with the CSET Multiple Subject test], I passed! I got the good news yesterday, and I am so excited :) Thank you! I can now move on in my teaching/graduate program with this behind me. Many thanks for your patience and dedication to my cause! I would recommend you to any of my peers in need of test prep. Thanks again!"
Leigh F. - February 2nd, 2010

"I really appreciate your help. [..] I will definitely refer people to you so that they can pass this dang test! Take care Juan, you are a big help. I would not be able to have got through Math without you [Nursing School Math]."
Veronica G. - February 1st, 2010

"Thank you Juan for all your help in this rigorous subject! Math has always been a struggle for me, but with the one on one help I was able to see a tremendous change in my confidence level, especially when taking the SAT math portion. My score has increased dramatically with your generous help!."
Holly K. - November 28, 2009

"I wanted to thank you for helping me to prepare for the GRE. I would not have been nearly as well prepared for that test if you had not sought to communicate a clear understanding of the nature of the concepts that define the mathematics discipline, for the benefit of my learning and preparation. With the level of mathematics knowledge that is tested for with the GRE, I found in reflection that your sessions were very enlightening and valued. The clarity that a rigorous review can do for not only one’s preparation but appreciation is sincerely profound. Taking your preparatory sessions has contributed significantly to doubling the score I was able to get potentially and actually. Thank you very much again and I wish you long life and prosperity."
Christopher C. - October 11, 2009

"Thank you Juan for all you have done to help Niamh with her math. This was definitely a subject that she had struggled with. Since she began tutoring with you she has developed a much better understanding of the math concepts. Her teacher has seen a difference and Niamh has much more confidence with her math. We just received her SAT results and they are much better than they have been in the past. We really appreciate your hard work and dedication."
Ciara C. - May 24, 2009

"Well I wanted to share with you that I finally passed the Cbest, on May fourth. I improved my score nearly double thanks to your help. My score went from 26 to 45, which is a whopping 19 point increase with your tutoring help. Thank you again."
Jeannie I. - May 18, 2009

"I did tell you that I ended up with 690 on the GMAT, right? It was a good score for my purposes. I am accepted at the PhD program at University of South Florida. :) Thanks for all your help."
Maia F. - March 16, 2009

"The only class keeping me from a 4.0 GPA has always been my math class. Math has always felt impossible. However, Mr. Casteneda's tutoring has changed all of this! I just took my first Calculus exam, and scored 105 out of 100, so over 100%! His tutoring has helped me to not only get over my Math anxiety, but helped me to master the subject."
Colette D. - March 10, 2009

"I wanted to write to you and let you know that thanks to your help I have passed the CBEST - math portion with flying colors!!!! I made a 48/50!!!!!!!!
Thanks again for all your help, tips, and advice! Mil Gracias!!!!!!!"
Alexa E. - February 23, 2009

"Mr Castaneda worked with our son for about a month on Physics and Math tutoring in our home. He is very professional, prompt and pays attention to detail. My son enjoyed working with Mr. Castaneda, as he has a very easy going manner about him. I highly recommend him to anyone seeking math tutoring for their son or daughter. We would use him again in the future."
Karen C. - January 5, 2009

"I just wanted to thank you for helping prep me for the CBEST. I just got my results today-I PASSED! I improved my score by eight points!
Thanks for your patience and your help. I would recommend you to anyone who needs a tutor."
Leigh F. - October 20, 2008

"[...] I just wanted to let you know that I finally passed the CBEST, thanks for your help. I will definitely refer you if ever the opportunity arises."
Lisa L. - September 3, 2008

"I PASSED [...] I just wanted to let you know that I got a C+ as my final grade in Statistics and scored a 71 on the final. [...] Thanks!"
Kelly L. - May 28, 2008

"I passed! I passed! I passed! Yeah... And you know, the most grotesque thing is that I have the highest score in math! That is so funny!
Thanks so much for all your help. I really appreciate it!"
Ulrika P. - April 28, 2008

"You tutored me the first couple weeks of December towards the end of my first quarter at UCSD. I really appreciated all the help and I did well on my calculus final. :) [...] Thanks!"
Paulina A. - January 11, 2008

"[..] THANK YOU! I passed the CBEST Math section and actually scored really well. [..] Focusing on fractions, percentages, and word problems was really beneficial."
Felix S. - December 18, 2007

"I wanted to thank you for your help with my Calc 2 class. I ended up far surpassing my expectations and getting an A. Thank you once again."
Steve H. - November 13, 2007

"[...] I took the GRE last week and I got a 660 on the math section! I was so surprised, and really want to thank you for all of your help. I certainly could not have done it without you."
Debra K. - October 14, 2007

"The problem sets aren't collected, but your work definitely shines light on some issues for me, and is extremely helpful.. They are also written in a very clear style, so that also works very well. You have a genuine talent for writing up solutions that can be understood by the student. I very much appreciate your help."
Robert A. - October 7, 2007

"I am not sure how I did it but I passed with flying colors!!! Thank you for all your help!!!"
Caroline G. - September 27, 2007

"[...] I just got my CSET results in today and I passed!! I am sooo happy, and thankful. I wanted to thank you again for all your time and effort tutoring me on this test. The test itself was tough and very challenging, but I am so glad that I overcame this test with your guidance and support which led me to a passing score!
Thank you again Carlos, and I will be passing along your number and e-mail address to my friends who still need to pass these tests in order to become a teacher (CBEST & CSET)."
Shawna R. - August 20, 2007

"I transferred into a university and was unable to take a Calculus one class. I didn't want to get behind in my studies so I decided to clep. However, I was told that I would have to clep Calc. 1 and 2 or none at all because they didn't have a clep test for just one. I really needed help, but all the people that should have had the knowledge either didn't have the time, or really maybe didn't have the knowledge. I was looking for help online and found Carlos' site. I thought it was great, and was very dissapointed when I realized his services were in California and I am in Arkansas. I sent him a little e-mail anyway. Long story short he made it possible to help me by phone and online. I passed the clep test with a 67 which is 17 points more than the 50 I needed. I wondered how just a few sessions with Carlos could be so helpful. I think its because all you have to do is say a problem and he's right with you. He doesn't fumble around trying to figure things out and losing precious time. The bottom line is he knows his stuff and is capable of helping me and anyone else know it too. I'll be meeting with him regularly until I graduate with my BA degree. Everyone from Maine to California should consider Carlos if in need of good and serious help on math."
November F. - August 20, 2007

"Hurrah. Jim passed the ELM. Yippee. [...] Your tutoring really helped him prepare for the test. Thanks,"
Theresa T.- June 11, 2007

"Recently I successfully passed the FBI’s Phase I examination. Due to Carlos Castaneda Tutoring Service I was adequately prepared and had the confidence to handle the mathematical problems encompassed within this examination. I highly recommend this tutoring services for any aspiring professional and academic scholar. Thanks Carlos"
Ryan - April 6, 2007

"After quickly cramming for my first GMAT exam, I did not do well. I was rushing to get a Round 2 application out to the top tier B-schools and knew that I needed help. I called Carlos who met with me nearly every day for a month. I took the GMAT again on December 30th and raised my score by over 100 points!!! I applied to over 5 schools during the next week and just got accepted to Wharton Business School. I AM SO EXCITED! I could not have accomplished this without Carlos' instruction. He helped me to develop a strategy for approaching all questions and gave me the confidence in myself to succeed on test day. I will recommend Carlos' tutoring to anyone and am happy to speak to anyone looking for a reference (just ask Carlos for my e-mail...). Carlos, thanks again!!!"
Jennifer C.- March 27, 2007

"I wanted to let you know that I passed the GRE. [...] the department was happy with the score. [...] Thank you for your one tutoring session with me. [...] it helped me feel more confident and I really needed that."
Suzanne J.- February 28, 2007

"I have good news. Thanks to you I passed my CBEST Math retake test. My grade went up 10 points. I want to thank you for all of your help. You are a great tutor and I am glad that I had the chance to work with you. I would be more than happy to recommend you as a math tutor. All the best-"
Christopher L.- January 2, 2007

"I just wanted to write you a quick e-mail letting you know I got my results back for the CBEST today, and I passed! I was SOOO excited. Again, I wanted to thank you for all your hard-work and the numerous visits to Mira Mesa to help tutor me. I will keep you posted on CSET tutoring (which I'll probably sign up for after the holidays). I'll keep in touch, and thank you again for everything!"
Shawna R.- December 19, 2006

"[...] As for your tutoring, I could not ask for anyone better or more knowledgeable. You really boosted my confidence and those extra 20 points were all thanks to you. I thought that you answered questions in a meaningful and memorable way and I enjoyed working with you. Thanks so much."
Emily G.- October 31, 2006

"When I was studying for the GMAT, I knew the basics of math. However, Carlos helped me get to the next level and improve my test score by more than 200 points! Thanks Carlos!"
Juanita P.- October 17, 2006

"I came to Carlos for help raising my GRE math score. Not only was I successful in completing that task, my confidence and self-assurance were raised also. Carlos is an excellent tutor- he is patient, smart, and makes math easy to understand and learn. I highly recommend him to anyone who is in need of help. I had a wonderful experience."
Marcy L.- October 7, 2006

"Wow thanks so much Carlos! I thought I was doing something wrong; if I ever come across another problem I'll be sure to ask you.
[...] Thanks for your time and help!."
Angela - September 15, 2006

"Just a note to let you know I passed the Linear Algebra class...90% on the final...and to thank you for your help.
[...] I'll be taking more math classes in the future so let's keep in touch. Thanks again."
Barb W. - June 28, 2006

"I wanted to thank you for all your help. I ended up getting around 900 on the GRE which I am very happy about and I owe it all to you. Thank you so much!"
Stacy B. - June 5, 2006

"Just to let you know I got a B in the math class. I told you I'd let you know and I just found out =) Maybe we can get back together when I start up stats in the Fall."
Katherine R. - June 2, 2006

"I got a 710. I could not have come close to this score without your help and encouragement.
You're an excellent tutor, and if there's anything I can do to help (serve as a reference), etc. just let me know.
(For example, you can now say you've raised a GMAT score from 620 to 710). Thanks for EVERYTHING."
Jon S. - May 30, 2006

"Given that my goal is a 700, I'm feeling fairly (but not overly) confident. I'll let you know what I get tomorrow.
I know that regardless of what I score, I would have scored lower if it weren't for your help and encouragement..
You were an excellent tutor, and for the first time - helped me actually LIKE math!"
Jon S. - May 29, 2006

"Dear Carlos,
We only met one time for math tutoring. However, that one time made it possible to understand what was foreign to me in algebra.
Because of your teachings, I passed the CBEST test. Thank you for your help."
Rick M. - May 18, 2006

"Carlos is an incredible math tutor. He has an incredible grasp of math concepts, and he can explain difficult material in creative and easy to understand ways.
When I started studying with Carlos I was getting around 660 consistently on the GMAT with a math score in the 60th percentile.
By the time I took the test, I had scored as high as a 770, with my math scores well over the 90th percentile."
Ian M. - May 9, 2006

"I took the CBEST last weekend and I think I did well. Mostly because of all of your help.
I am going to be studying for the CSET now and I will DEFINITELY need your help."
Katie A. - April 30, 2006

"I just got my scores on the CBEST and I got a 68 on the math - I passed!
My original score was a 27 so I made awesome improvement, your tutoring really helped!
Thanks so much, I'm so glad I can get rid of the study guide and move on with my career. I'm happy to be a reference for you for future students....
Thanks so much!"
Cara S. - March 6, 2006

"I recently sat for my exam, and I passed with flying colors. Thanks for all of your help!"
Scott T. - February 17, 2006

"I passed my Precalculus course, thanks so much for helping me reach that goal!"
Zac C. - February 1st, 2006

"I appreciate everything you've done for me in helping me to prepare for the math portion of the test.
I mean it when I say that you're the best tutor I have ever had."
Marc H. - January 13, 2006

"Dear Carlos,
On behalf of my family and myself, we want to thank you for your help in tutoring me for the CBEST, I received my scores today and I finally passed the math section!
Your assistance was invaluabe, as there were questions that I could not have answered without your help. Now off to get my credential and a job!
Muchas Gracias, "
Ericka Z. - December 19, 2005

"I did pass the test. I actually doubled my score. Thank you for all of your help!"
Eliza - October 2, 2005

"I definetly passed it and did the BEST on the Math portion!
I receieved 580 out of 800 points on Math!!! :) ...more than I need for acceptance into grad school! !!Yay!!!
And it was all because of you! Thank you so so much, Carlos.
Your intelligent, tutoring skills, patience and time were invaluable to my results."
Amelia G. - September 27, 2005

"Thank you much for the tutoring sessions, it was a good warm up and intro back into math.
If it turns out I need help with the online class as well, I'll keep your number so you can tutor me again."
Keoni - September 4, 2005

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Last review: May 23, 2018