The Catholic School of St Gregory The Great Believe and Achieve

Mastering Number

Mastering Number
At St Gregorys, we follow the Mastering Number programme produced by the National Centre for Excellence in the Teaching of Mathematics (NCETM) for our EYFS maths lessons and our Number Sense sessions in Years 1 and 2. 

The programme aims to develop solid number sense, including fluency and flexibility with number facts. The aim over time is that children will leave KS1 with fluency in calculation and a confidence and flexibility with number. 

Mastering Number is followed in EYFS, Y1 and Y2. 

In EYFS, the Mastering Number programme is used as the core planning for maths lessons that take place four times a week and continuous provision activities.

In Years 1 and 2, we use the Mastering Number materials in our Number Sense sessions. These Number Sense session are additional time outside of the maths lesson for fluency practice and retrieval of learning.


Manipulatives and representations
The core manipulative used is the rekenrek. The rekenrek is a maths counting frame that has 2 rows of10 beads, totalling 20 beads. Each row has five red and five white beads that can be easily moved along the rungs. The rekenrek is a hands-on resource that helps children visual and learn essential foundations in number. These include:

  • Visualisation of number: subitising, five and a bit, ten and some more, odd and even
  • Place value and the structure of our base-ten number system
  • Counting
  • Automatic recall of number facts
  • Composition of number
  • Cardinality of number – the ‘howmanyness’
  • Bridging ten
  • Compensation
  • Commutativity
  • Ability to transfer learning to related facts
  • Strategies for addition and subtraction
  • Strategies for doubling, halving, adding on, etc.


Further representations used in the Mastering Number programme include: Numberblocks, counters, dice, the tens frame, multi-link, images that mirror the rekenrek (birds on a line, children on a bus), fingers.


Video links
Leading the programme is the NCETM’s Director for Primary Mathematics, Debbie Morgan, who was also a maths consultant for the Numberblocks television show on CBeebies. She explains how the abacus-like rekenrek can be used to help children develop confidence and fluency with number. Watch HERE.

The next clip shows students using the rekenrek in a variety of ways to support and show their number fluency such as subitising, composition and cardinality of number.  Watch HERE.