NSM Number Facts Principle 6
Teaching derived fact strategies leads not only to fluency in number facts, but also to an understanding of number relationships
Derived fact strategy approaches lead to children becoming more confident in their number facts, as discussed in Principle 5, and the strategies in themselves can continue to be drawn on going forward [3,4]. Once children have realised they can calculate 8 + 5 by thinking 8 + 2 + 3, then can apply this approach to larger calculations. For example, 98 + 36 could be solved by thinking ’98 + 2 + 34’. The type of thinking that this approach teaches has long term benefits for children.
Application to NSM Number Facts
NSM Number Facts has a defined set of 12 calculation strategies at the core of the programme. The strategies are explicitly taught with relevant groups of facts through Stage 3-5. Stage 6 then focuses on extending the application of these strategies to calculations involving large numbers.
 ASKEW, M, BIBBY, T & BROWN, M 2001, Raising attainment in primary number sense: from counting to strategy. BEAM Education, London.
 THORNTON, C.A., 1978. Emphasizing Thinking Strategies in Basic Fact Instruction The Journal for Research in Mathematics Education, 9 (3) 214-227.