Let me say this. I believe some of the questions may be too difficult for 4 years old, or even 6 years old. However, some of the questions are doable. I have to admit that I am quite surprised with what kids (my daughter and her classmate) can do. I won't recommend this book to all parents, but if the kids have interest in this area, worth a try. The questions may be similar to olympiad math questions. Honest, I don't think every kid will like this book.
Some questions are really very difficult. How did I coach my kids? Well, I explained those difficult questions, give clues. With that, my daughter can do many of the questions. If she cannot do the question, I told her that it's OK and I will teach her how to do the questions. Sometimes, I have to look at the answer too. :-) She even brought this to school and "finished" the book on her own but she left it blank if she did not know the solution.
If your kids like Maths, show this book to them and see whether they like the book.
P/S: Thanks the author for writing this book.
