My son is a trainee primary school teacher, teaching at a local primary school; this is his review:
This book is easily read and understood, with its colourful images (that had an additional, if slightly distracting, bonus of starting discussions about food and games!) and clear instructions. Some of the 'big' words, such as 'subtraction', 'doubling' and 'halving' needed to be explained to the children in simpler terms, but the images helped. It definitely made learning fun.
It is a book aimed at three separate year classes, so don't expect a 5yo to finish it; it needs to be used in conjunction with what is being taught in class. However, if you do want your child to get ahead, this is a very good book to start with, and if you're not very good at Maths yourself, it's easy to refer to the (removable) answers section.
It is great value for money, as the pages can be rubbed out, and the book can then be used as a refresher. It is a 2013 edition, so is in line with curriculum.