India**

I especially like a sentence in the book: "These methods will improve students' calculation abilities in addition, subtraction, multiplication and division. They will not only improve students' math scores, but also change their way of thinking." This sentence really makes sense. Learning these methods is not only helpful to students, but also useful to us adults. It can change the way we think and make us more efficient at work and life. I think this book is very suitable for everyone to read, and you will gain a lot!

Some algorithms are really useful, and some are not as useful as vertical calculations.

Good book, worth studying!

Very good! Especially finding cube roots is really easy.