Testimonials

You can read about my background as a test-prep tutor and developer by clicking here, or read more about the services I offer in person or by phone.

Please note: Total GMAT Math and Total GMAT Verbal were formerly known as The GMAT Math Bible and The GMAT Verbal Bible. For the sake of clarity, I've replaced the old names with the new names in the quotes below.

Total GMAT Math (and other books)

Now that students have been using my books to ace the GMAT for years, there are plenty of positive reviews and testimonials on sites other than this one. I've included some of those in addition to a sampling of the e-mails I get from happy customers.

Over at Beat the GMAT, user dkrich reports on how he got a 750:

I found Jeff Sackmann's blog, gmathacks.com to be very important to my preparation. I purchased his Total GMAT Math, printed it out, took it over to Kinko's, and had it bound. Then I worked through every chapter, and I revisited some several times because I just didn't have the concepts nailed down. I highly recommend making his materials an integral part of your preparation if you are rusty in math, and I assure you that I am receiving no monetary incentives for that endorsement!

Elizabeth got a 770!

I purchased two of Jeff's books: Total GMAT Math and The Official Guide to GMAT Review. I cannot stress enough how vital these books were to my study regimen. They are absolutely and completely responsible for how I performed on the test. Because the OG doesn't offer good explanations, doesn't rank each problem's difficulty, and doesn't have good math review, these books will fill in those gaps for you. I hadn't taken a math class since my freshman year of college 6 years ago, so Total GMAT Math saved me. I started each study session with one chapter from Total GMAT Math.

Carrie hadn't done any math in more than two decades, but my books helped her get a 720!

I purchased the PDF books from GMAT Hacks (www.gmathacks.com) and these were great, especially for re-learning the math. The math book goes subject by subject through math teaching it. I did the books and all the questions in them.

Here's Chad J's story (or click here for the full version).

I ordered Total GMAT Math and went through it religiously (pun intended). I went to work first through Total GMAT Math, then took that information and worked through the questions that I did in the Official Guide. As I worked through the guide I also had a look at the vast majority of your articles on the website. These were the only three references I used in my five-week study period.
 
I wrote the GMAT exam yesterday, 9 April, and received a grade of 760 (Quant: 48, Verbal: 47). I certainly didn't think that was possible a little over a month ago, and I largely attribute my success to the clear and concise explanations you provide in both Total GMAT Math and online articles. If anyone asks me for advice in preparation for the GMAT I will let them know that your book is a must-buy, and your website a must-bookmark.

At Beat the GMAT, Ram reports on his hard work, which paid off to the tune of a 680.

...I stumbled across a website (www.gmathacks.com) that contained the most insightful of articles about GMAT. I read almost every single article in this website as it had answers to every single question that I had. I strongly recommend that this website is a must have for every GMAT aspirant.
 
To Improve Content Knowledge:
GMAT Hacks - Total GMAT Math. This really should be your bible for content knowledge development for the Quants section.

The Time for the remix blog reports on the best ways to prepare for the GMAT:

You need to go to www.gmathacks.com and buy damn near everything that Jeff Sackmann offers especially Total GMAT Math and any problem sets that you are having trouble with. They are well worth the money and will definitely help you.

Brandon found that Total GMAT Math made all the difference. You can read the full version of his post-test report here.

Having used virtually every study material available (OG, Princeton, Kaplan), Total GMAT Math is far and away the best study material available. Princeton Review's Math Review is junk in comparison. It was the best $50 I've ever spent.

Ryan scored the magical 700!

I'm sure you hear this all the time, but I just wanted to thank you for creating such a great, concise, easy to read GMAT package. Of all the GMAT books I purchased, your books - I bought both - were the most concise and effective.
 
I just returned from taking the exam and received a 700 score...not bad for someone who historically has been pretty poor at math (no longer!).

Leila can't be beat for hard work:

I absolutely adored your study materials. They were so helpful and I am grateful that your problems are a resource for gmatters. I mentioned before that I literally did all 1800 problems (am I the only weirdo who thinks that permutations and probability questions are fun?), and I read each answer explanation as well.

James is applying to b-schools now that he's armed with his 680:

Again, thanks for your advice and best of luck with your GMAT tutoring. Your methods and resources are definitely the best out there.

Iesan used my resources to go from a darn good score to a great one!

Just wanted to say that your Total GMAT Math & challenge materials were extremely helpful. I went from a 670 to a 730 this past November. In fact, my quant went from a 39 to a 47. Thanks!

Tanuj came home from the GMAT with a 710--pretty good after starting with a 570!

I took my GMAT on Dec. 6th and received a 710 (Q48, V38). My first diagnostic test was a 570 - a free online Princeton Review test. To be fair, I have never seen Data Sufficiency problems, so that may have affected by diagnostic score.
 
Your Total GMAT Math was the only math resource I needed other than the last 100 questions in each section of the OG, and repeating the GMATPrep software tests over and over for new problems. Really amazing resource and worth every penny.

Frank used my materials to get over the 700-score hump:

Your Total GMAT Math rocks! I followed your advice on setting a 2-hr per day schedule, studying the OG and of course Total GMAT Math. Happy to report that my score increased from 670 to 710. Thanks for all the helpful tips in your blog.

Whew! I hope that, soon, I can add you to this list.

One-on-one Tutoring Clients

In the past few months alone, several of my students have scored a 700 or higher, including a 750 and a 770! Here's what a few of my clients and readers have said about me.

Alex won't need to take the test again!

I just got back from the GMAT. I got a 750!
 
I wanted to say thank you for all of your help. The majority of my success on the test was due to our tutoring sessions. Not that you need it, but if you ever want a student to give you a reference for any reason, please let me know, I would be happy to.

Victoria took the test twice, and her second try came after a few months of hard work, including meeting with me 2-3 times per month:

Anyway my second and final score is...740!! Q48 V44. Thank you!

Adam improved his score from a 620 to a 690, and is now studying at Wharton:

Your tutoring was exactly what I needed to dramatically improve my score. Thanks again!

Jim hadn't looked at a math problem in nearly a decade, yet climbed all the way to a 680 on test day!

Thanks for all of you help over the last several weeks. I couldn't have gotten this far without it.

Kyle M. had taken the test before, but after several sessions with me, she got the score she needed to get into the program of her choice:

I just want to let you know that I was accepted at Columbia Business School - Executive Program and will be attending this fall. Thanks again for all of your help with my GMAT. It's nice to know that all the hard work finally paid off :). I keep referring my friends to you for GMAT help, so hopefully you'll see some of our other friends soon too!

Taylor met with me twice, and will never have to think about the GMAT again:

I re-took the GMAT and scored over 700, which was my goal. Columbia admitted me a few months ago, so I'll be heading there in the fall.

One meeting was enough to help Ray achieve his goal:

I took the test on Friday and boosted my score by 40 points to a 680. Although we never ended up meeting for a 2nd time, the information on your website, the OG explanations and your newsletters especially were very helpful.

After several weeks of tutoring, Jillian improved her score by more than 200 points!

I did it!!! Can you believe it? Thank you so much for all of your help. I could have never done it without you.

Everything Else

Kim found that my Number Properties: Challenge set came in handy on test day:

750 on my 2nd attempt! Much thanks to offering the number properties challenge, it really helped me in a couple killer questions. All of the tips on your website were also incredibly useful, I referenced the tips list several times over the course of my study.

Pierre was able to put my advice to good use:

You have the best website out there discussing the GMAT, from its layout to the diversity of topics covered. Your explanations are clear and to the point which is refreshing considering the amount of useless info one has to go through in order to get to something interesting on other websites. Following some of your guidance I got a 680 today on the test.

Kyle S. scored nearly as well as I did:

Thanks for your GMAT tips blog. I just took the test today and using a combination of two books (the kaplan gmat and gmat 800 books) and your blog, I scored a 760! I couldn't have done it without your advice.

I always love triple-digit GMAT score increases! Mike wrote in with his story:

I found your site to be an excellent source of information in preparation for the GMAT. I first took the GMAT last Feb. and did not score well. The problem was the material and method I used to study. After several months of preparation and utilization of tips from your site - like purchasing the Official GMAT Guide, avoiding long division, and factoring - I improved my score by 130 points. I also found your guidance to be very positive in nature yet honest in helping me establish a realistic score goal.

Jessica found that my advice was the missing link:

First of all, I want to say thank you for all of your great posts. I took the GMAT on December 30, and prepped using the Kaplan book/cd and math study guide. While I felt comfortable and ready for the material, I still felt like my test attitude and mental readiness were lacking. Your blog helped round out some of the edges and helped me look at the test differently. Reading your posts was like having my own coach, and I truly appreciate it. I didn't feel like I was alone on test day.

Ryan is ready to move on to the next step:

I again just wanted to extend my thanks for creating and maintaining the site. I took my test yesterday and achieved my goal. You're advice was complete and utterly sound, and I will be certain to recommend your site and study materials to any potential test taker.

Charles couldn't have done much better. In fact, if he ever wants a career change, perhaps he should consider GMAT tutoring!

Jeff, I just wanted to thank you for your tips and practice problems. They helped me get a 770 on the exam last Saturday. I will definitely recommend your site and your books to my friends who are studying for the GMAT.

Arthur discovered that my exclusive problem sets were exactly what he needed:

These banks of questions are excellent. I am finding them an enormous help.

Ryan K. recently earned a score that will get him strong consideration at whatever business schools he applies to:

With much help for your website and practice problem sets I scored a 750. Thanks so much for all you do - it is very much appreciated. In fact, I've got a few of my co-workers hooked on your site.

Kareem looked far and wide for quality GMAT advice on the web, and finally found it here:

There are alot of GMAT related websites on the web but your site is by far the best. You give honest advice and tips that will work.

Tell Me Your Success Story!

If my resources or tips have helped you meet your goals of scoring well on the GMAT and getting into the business school of your choice, drop me a line. I'd love to hear about it!

About the author: Jeff Sackmann is a GMAT tutor based in New York City. He has created many resources for GMAT preparation, including the popular Total GMAT Math and Total GMAT Verbal, as well as 1,800 practice GMAT math questions.

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Total GMAT Verbal The comprehensive guide to the GMAT Verbal section. Recognize, dissect, and master every question type you'll face on the test. Everything you need, all in one place, including 100+ realistic practice questions. Click to read more.