[DanBC]

> They cannot help their children. The math makes no sense and seems to offer no practical purpose other than it is new.

First of all parents were not able to help their children with old methods either. Give someone a pen and paper and ask them how to add 17% to 58. You don't want an answer - just a working method. A lot of people can't do this on paper, but that's okay because we have computers to do that stuff. Lots of people can't add 17% to 58 using a computer. I find that a bit scary.

Going on to the example: I'm pretty stupid; I've often said that I am hopeless at math. I found that single example really easy to understand. I've not had any exposure to similar examples. I don't believe the author is actually baffled by the example. Perhaps a book might help?

http://www.robeastaway.com/books/maths-for-mums-and-dads

> What on earth are number bonds? What are partitioning and chunking? And why does my child look blank - or have a tantrum - when I demonstrate long multiplication? This book is for mums, dads and grandparents who want to help their primary school children or grandchildren with maths. To do so, many parents find they need to overcome their own rustiness and also to learn the strange new methods and terminology. Throughout the book are games, puzzles and examples of amusing ways in which kids ingeniously 'get it wrong'.