NSM Number Facts Principle 7
The automatic retrieval of basic maths facts is critical to solving complex problems.
As children meet mathematical problems in life and school, they need to focus on how to break them down into steps in order to solve them. Each step in an additive problem draws on the building block addition and subtraction facts. Before these facts are learned to automaticity, calculating simple arithmetic facts requires working memory (i.e., the mental “space” in which thought occurs). With enough practice, however, the answers can be pulled from memory (rather than calculated) thereby incurring virtually no cost to working memory. Students who automatically retrieve the answers to simple addition and subtraction problems keep their working memory free to focus on the bigger problem .
Application to NSM Number Facts
NSM Number Facts moves all children beyond counting, enabling them to fluently recall or derive their addition and subtraction facts. The programme involves regular assessment and targeted follow-up to ensure this is achieved. The ultimate aim of NSM Number Facts is to make sure that a lack of automaticity with addition and subtraction facts is never a barrier to accessing mathematical concepts and problems as children progress beyond KS1 maths.
 WILLINGHAM, D., 2019. Is It True That Some People Can’t Do Math? American Educator, 14-19.