Secrets of Mental Math: The Mathemagician's Guide to Lightning Calculation and Amazing Math Tricks

This is a fun book for adults and children who like math and convenient mathematical tricks that will allow to quickly solve a variety of math problems in your head. This book makes math fun! Recently I visited family in Chicago. My great nephew is inquisitive and is advanced in math. Our mutual love for math makes it very easy to communicate with this youngster. Although he is only 10, I was able to teach him one of the tricks in the book that most adults do not know. If you want to square a two-digit number that ends in five, the last two digits always end in 25. To discover the digits that come before 25, multiply the first digit by itself and add the first digit to it--for example 35 x 35, 3 x 3 + 3 = 12, so 35 squared = 1,225. Another example is 95 squared. 9 x 9 +9 = 90, so 95 squared = 9,025. There are 231 easy to follow pages in this engaging book with numerous tricks and problem solving techniques with answers that follow the problems or in the back of the book. Though my great nephew is hampered by a medical condition that is not conducive to good communications with some people, his math skills are far beyond his age. I know that he will be intrigued and have a blast with this book and can hardly wait for him to use it. This book will not only make you seem smarter, it will make others think you are a mathematical whiz and they will be correct. Math can be and is fun when you master books like this one. Enjoy! I recommend Secrets of Mental Math by Arthur Benjamin and Michael Shermer to friends, family, and others who would like to increase their mathematical skills in a fun and easy manner.

I'm a near-geezer age character and long removed from the academic, high level mathematician rigor. I remain operationally proficient in Mathematica to work that occasional problem when I need an answer without having time to revisit the physical, chemical or mathematical process. This book is not about mathematics but arithmetic. If you're in science or business, you are an arithmetician by trade. High speed, close enough mental arithmetic is critical to the trade. Simple arithmetic remains the great divider in critical thinking from those that can think and those that stumble. If you stumble, you know you stumble. I know mathematicians that can't balance a check book or conceptulize GAAP P&L or Balance Sheet mechanics. I've imagined myself a seasoned veteran in `close enough' mastery of columnar data, formula application, and simple arithmetic operations of a rote nature. I can determine the `range and unit measures' of the correct answer to a particular problem by the problem statement. It takes a lifetime to develop this skill from the rote arithmetic I should have paid more attention to it in elementary school, but ... it is what it is and it has to mastered. If you need a `correct' answer to 2 decimal places, use a calculator or Excel. If you need a fast approximation in the heat of mentally exploring alternatives use significance and proportionality to estimate within 5-10% of the calculated answer. That's usually performing well enough for fast critical thinking purposes. Remember that the equipment or source that provided the initial data is doing pretty well if it's within 5% of ground truth. In `Secrets of Mental Math' you can explore refining your arithmetician skill to 2 decimal places with only slight change ups in heuristic application. Why isn't this stuff taught in schools? I mean it is important to know why arithmetic works, but for gosh sakes ... can't education get to the chase and deliver the shortcuts (all mathematically based in the philosophy of mathematics) to get an answer using outside of the box methods? No one can be `damaged' by exposure to these methods. "Secrets of Mental Math" is an excellent consolidation of shortcuts and tricks to tune up you arithmetician trade. Our kids would benefit greatly if this or a similar text was included in a mandatory high school course called `Critical Thinking'. It would be a powerful primer for those that will never do a long division by hand again and for those that will go on to calculate chemistry and physics methods and equations. The answer is in the problem. Arithmetic is a tyranny. Do your kid and yourself a favor and try this powerful little book.

Okay - I'm going to start off with a 5 and I'll revise from there. I'll tell you why I am giving this score when I have not even received the book. I am a well educated individual and teach at a college level. My husband is a DVM. I want you to understand where I'm coming from here - I'm not an uneducated lout. So I saw this commercial on TV and thought hmmmmm....I have a daughter who struggles in math as well. I thought this might help her (and I might find it useful too). My husband was also intrigued. I did some research on the web and found one of his teaching videos (It's about a half hour long if you are looking for it). As I started watching, I thought...this guy is a quack. My husband even said "How much did you pay for that book?" I hadn't ordered yet...I was still trying to figure it out. So as I continued to watch, things started to make sense. He seems to use a combination of chunking and mnemonics to help you work with the numbers. It's not going to make you a math whiz - you still need to know how to do the basics (add,subtract,divide, multiply), but...if you can do the basics, it seems that this will make you able to expand upon that knowledge. I'll add more after I get the book and start learning.... Okay - have had the book now for a little over a month. The information contained within is very simple to follow. At first, it seems as if it won't work, but with practice, it actually makes difficult math problems easy. It's more for straight calculations (addition, subtraction, multiplication, division) rather than the higher level critical thinking involved in algebra or calculus, but it definitely makes those quicker as you don't have to take the time for the basic math. The memorization skills taught are also very useful. I have difficult putting names to faces, but now - it is much easier. It's basic association and mnemonics, but the tips are very useful. All in all, this is a very good book.

I am totally updating my initial review of "Secrets of Mental Math" because I am more than enough of a Man to admit when I am wrong! My initial review was fueled by frustration that should have been directed at the awful school system we suffer from (I LOVE America, I do NOT like out school system, grade school, jr. high, highschool--I really enjoyed and learned a lot in College:) Anyway, I locked myself in a quiet room with "Secrets of Mental Math" a pen and paper and some hot, strong coffee and I FORCED myself to do all the examples and read until I did find the "how to" (initially they just show off and this pissed me off because it reminded me of the smart kids in the front row that answered every question easily and mislead the teachers into thinking we all understood how to do things when in fact most of us were almost "drowning" and stuggling just to pass the class and the teachers just wanted to teach to those bright students and left the rest of us in the dust--the authors totally show off yet they also teach ) So now after a few days of practice I am actually able to do some cool math magic, even in my head! I am a bit Math Dyslectic (not sure if this is a real learning issue, yet I know many people tend to "switch numbers" when they are under stress and I got many "wrong number phone calls" over the years from people trying to dial a 948 and instead they misdialed a 984 and so got the wrong number. I sometimes do this with addresses too and I know I had "bad math teachers" who actually used "bad hypnosis" to program me that "you just aren't good at math, be glad you are so smart in most other subjects..." So I deprogrammed myself with Self Hypnosis, NLP, EFT, etc. and now I know to be really careful of my "bad habit" of "switching numbers" and also of using tiny corners of pages to do arithmatic and so I can barely even read my own handwriting (this comes from the "you have to show your work or we think you are cheating" from bad school systems because early on I learned to be good at math from my European born mother and I "got in trouble" with the schools for "doing things my way" and eventually they just confused me so much that I "WAS bad at math" and now I am actually quite good and improving all the time. My apologies to the very good authors of "Secrets of Mental Math" and I am grateful for their very good book and glad I am stubborn enough and open minded enough to give things another try and so I can learn better and be more Limitless :) Michael Twomey

I use some of the showmanship tricks from this book to teach math. Math, like any subject, should be challenging, energizing, and fun. I also have been using this book as a prize and reward to motivate young students. The swagger and confidence that they have as calculating squares of two digit numbers in their heads has been fun to watch. That they can beat calculators teaches a self reliance and that a calculator is extra baggage to lug around. Fourth graders struggle initially, but as they learn their tables, they see the power of being a super brainiac. I have been using the methods in this book as they are learning, to reinforce what they are learning. Young minds are blown as they tie concepts together. This isn't a comprehensive textbook, but is more entertaining. It raises the magicians curtain to expose some of the secrets of show exhibition math. After learning single digit multiplication is an ideal time for students to get this book. A caveat, though, the algebraic proofs will be above their learning, but is also a soft introduction to algebraic concepts. It fits well with how math is now taught.

I know most of the the basic Math problems and how to solve them using a calculator but I needed a refresher before going back to school. After seeing those 5-8 year old kids on T.V. doing math in their head I kinda though it was cool. Those kids are going to be successful and maybe I can learn also? Well, I bought both of the top selling books on Amazon regarding shortcut to math. I'm that type of person that can't stand prolong reading and want to learn everything now! I bought this book as a back-up and the the other book with the less pages as my main choice. Well fortunate for me I bought this book because the other book with the shorter pages expected me to know everything about math and dove straight into the deep end. I actually started to drown. Not only that, but it was not an enjoyable read at all. It was like going back to school which put me off learning Math to begin with. I kind of knew it wouldn't be all fun and games but it couldn't be this hard right? Well it's not. This book is pleasant and fun to read. Everything is laid-out. This book covers it all from start to finish. It's very easy to follow and I never felt challenged once. Everything is step by step and at you're own pace with good instruction and examples. Well worth you're money and enjoyable to read also.

My 13yo is great at math with a calculator, but not without one. I remember learning a bunch of mental math tricks when I was his age, so I was looking for a resource that collected those tricks and tips in one place, so he could study and use them over time. This book is perfect for that. It's really well-written, easy to understand, and appropriate for kids (and adults) over about 10. He got a lot out of it, and I got an incidental refresher course. Highly recommend.

Really!! Buy this book! I loved and excelled in math as a child and all through my adulthood but WHOA!! THIS BOOK!! From the very first pages, this book masterfully uses the distributive, commutative, and associative properties taught in elementary school along with really neat "tricks" to help the reader see, appreciate, and be wowed by the beautiful relationships of numbers. Arthur Benjamin reignites the fun in math and makes it wonderfully and simplistically clear how learning this aspect of math does not have to be the frightening, boring, mechanistic, drill-and-kill, painful experience that far too many of us grew up with and far too many children still have. Well written and well sequenced, each page gives simple, mind-blowing steps to boosting your mental math power! Do a little each day and you'll impress yourself and your family and friends with you newfound math skills and confidence! :) ENJOY!!