This is the first of a series of 4 books introducing children to algebra. It is based on a recognition of generalized algebra and starts by giving children experiences with number. This then helps to improve their number bonds and starts their skills in generalized thinking. It is essential pre-algebra experiences. It does fit with common core but it is not the traditional approach. This is a child centered approach which involves action and reflection on that action. The teacher does have an input to look at these activities and see that we are developing the skill to generalize, by saying statements like ' they all go up in fives'. This is not a skill children are born with, they have to learn it and that is why this approach works and is so important.