Dedicated Year 1 resources for exploring related facts (fact families) within 20, reinforcing the inverse relationship between addition and subtraction, a key KS1 Maths objective. Activities build strong reasoning skills by requiring pupils to generate a set of four related facts from three given numbers. This small step supports deepening understanding of number relationships, a core requirement for national curriculum calculation mastery. The CS Maths Scheme provides structured practice to secure this relational concept.