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

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.

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.

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.