Advanced Year 3 resources for column subtraction with 2 exchanges (regrouping), extending the formal written method with multiple trades, a key KS2 Maths objective. Activities build deepening understanding of the exchange process across both the ones and tens columns, promoting reasoning and accuracy. This crucial small step supports mastery of formal subtraction and is vital for national curriculum calculation fluency. The CS Maths Scheme provides structured Base 10 and column format practice.