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'Knowing a half' and 'Seeing the whole'

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'Knowing a half' and 'Seeing the whole'

by Tabitha Gould & Fran Watson, 17 March 2026
Half an apple, with the other half cut into four pieces

Maths Week England has been running for six years now and is designed to raise the profile of mathematics and promote a more positive and inclusive approach to its enjoyment in all walks of life. Two of its primary aims are to make the subject accessible to all students and to help teachers with planning special, low-cost yet high-impact maths activities in their own settings.

Cambridge Mathematics' contribution in November 2025 was to offer teachers and their classes a chance to participate in a live webinar called "Fraction Exploration: 'Knowing a half' and 'Seeing the whole'". Teachers signed up to participate in one of two time slots and were invited to equip themselves and their students with paper, pencils, whiteboards, pens and dice for the expedition.

The who and where

Schools signed up from all over England and beyond!

A map view of England, larger placed ontop of a zoomed out map showing Pakistan on the edge. There is a pin on Pakistan, and on the larger map of England numerous pins

The what

The teaching and learning of fractions is a common talking point for practitioners as they attempt to balance the mathematical significance of the topic with the challenges faced by learners in attempting to make sense of the numerous new concepts and techniques. We explored this topic in the Cambridge Mathematics Framework (a network of mathematical concepts and ideas), creating what we call a 'submap' of fractions learning and this was then tied to England's National Curriculum objectives to focus the activities selected for this webinar.

Zoomed section of a larger knowledge graph, showing some nodes with mathematical titles

This highlighted two landmarks in the development of fractions concepts that we have called 'Knowing a half' and 'Seeing the whole'. A significant influence for both landmark ideas is a piece of research by Cortina and Visnovska (2015), which became the inspiration for the tasks and games which we designed to provide opportunities for discussion, reasoning and representation of these ideas on a number line.

The how

The bitesize tasks and discussions in the webinar gradually build up to these dice games:

A slide from a presentation titled 'The sim is greater (or less) than the whole. The slide is explaining the rules to a dice game

Individual players, or pairs, score points during their turn for filling in one of the empty boxes with the number they roll on the die. The number they roll must be able to be entered into an empty box to continue or finish the game, otherwise they must miss that turn.

The images below capture a snapshot from two different games (A at the top and B below it). How might you answer the questions? And how do you think your students might answer?

Two photos of a small whiteboard, each is showing different stages of a dice game

Whether you use 1–6 or 0–9 dice, perhaps you'd like to explore the following questions:

  • When is it not possible to make two different fractions from rolling two numbers?
  • Is it ever possible to create two different fractions from rolling two numbers, which would end up on the same side of 1 when positioned on a number line?
  • Why can't you use a zero in the denominator position of a fraction?
  • How does the game change if you play collaboratively, roll all the numbers first and see how many different ways there are to fill the empty boxes?

The slides and webinar recording are linked in the resources section below. You might also find further inspiration from reading Tabs' blog To half and to hold.

We'd love to hear how you get on and for you to share photos of student work with us! Perhaps you've also got some ideas about what you'd like us to focus on for next year's Maths Week England webinar? Do get in touch and let us know.

Resources

Register for Maths Week England in the future

Watch the 'Knowing a half' and 'Seeing the whole' webinar.

To see the slides for 'Knowing a half' and 'Seeing the whole'.

Read Cortina and Visnovska's research

To explore more research about teaching and learning fractions, take a look at these:
Espresso 25: What does research suggest about effective ways to introduce fractions?
Espresso 40: What does research suggest about the teaching and learning of fraction equivalence?



Reference

  • Cortina, J. L., & Visnovska, J. (2015). Supporting students to reason about the relative size of proper and improper fractions. In M. Marshman, V. Geiger & A. Bennison (Eds.), Mathematics education in the margins: Proceedings of the 38th annual conference of the Mathematics Education Research Group of Australasia (pp. 181–188). MERGA.


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