The National Curriculum for mathematics aims to ensure that all pupils become fluent in the fundamentals of mathematics, including through varied and frequent practice with increasingly complex problems over time, so that pupils develop conceptual understanding and the ability to recall and apply knowledge rapidly and accurately. 

Why is it important to teach number facts?

Automaticity with number facts frees up the working memory to think about other things such as how to solve a more complex problem (Willingham 2009)

Having knowledge of number facts supports pupils to think mathematically as they can use them to reason, see structures and patterns and make connections (Baroody 2006).