Foundational Year 1 resources introducing the parts and wholes concept, the essential structure for addition and subtraction in the KS1 Maths curriculum. Materials use the CPA approach to establish the conceptual understanding that numbers can be partitioned and recombined, underpinning the part-whole model. This crucial first small step in addition and subtraction prepares pupils for calculation mastery and aligns with national curriculum objectives. The CS Maths Scheme provides clear visual aids to define the relationship.