Targeted Year 3 resources for column addition with 1 exchange (regrouping), introducing the formal written method with thousands, a core KS2 Maths objective. Activities employ the CPA approach to build conceptual understanding of exchanging 10 ones for 1 ten or 10 tens for 1 hundred, promoting reasoning. This essential small step supports mastery of formal addition and is vital for national curriculum calculation fluency. The CS Maths Scheme provides structured Base 10 and column format practice.