Foundational Year 1 resources on doubles facts within 20, a core KS1 Maths objective for rapid mental calculation and varied fluency. Activities use the CPA approach to establish the conceptual understanding of adding the same number twice, leading to mental arithmetic mastery. This key small step is essential for building a bank of known facts and meeting national curriculum expectations for calculation efficiency. The CS Maths Scheme provides engaging visual and practical support for doubling.