Summary: This book has a variety of tricks to make basic mathematical operations easier to complete, such as simplifying a subtraction problem by adding the same number to both of your original numbers.
Comments: I can only assume this book is intended for grade school students, because all of the tricks that are widely applicable are things I've known since I was like 10. The rest of the tricks are so specialized that you would probably have to look them up every time, which would almost certainly take longer than just doing out the long way (eg multiplying two numbers when their end digits add to 10 and their other digits match). If you know any elementary school students who are interested in math or if you need a refresher course in basic math, this might be a worthwhile book. Otherwise, don't bother.
