Further reading
This article on Manipulatives in the Primary Classroom by Jenni Back can be found on the NRich website here: https://nrich.maths.org/ 10461 [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)]
This research support provides further in-depth reading on how children learn number: http://www.nuffieldfoundation.org/ sites/ default/ files/ P2.pdf
This is the reference for the article by Richard Skemp:
Skemp, R. (1973). ‘Relational versus instrumental understanding. Mathematics Teaching’, vol. 77, pp.20–26.
This link takes you to an nrich web page with different methods of multiplication demonstrated: https://nrich.maths.org/ 5612
This is the link to an nrich article on developing the conceptual understanding of division: https://nrich.maths.org/ 5450
The nrich.maths.org website has lots of articles and activities about place value:
A story about absolutely nothing: https://nrich.maths.org/ 5598
Arrange the digits: https://nrich.maths.org/ 1976
Digit sum: https://nrich.maths.org/ 534