Introducing Build-Ups

What is it?

A unit introducing ‘build-ups’ as a visual tool for developing geometrical language and reasoning.

There are seven build-ups, presented in two formats:
  • templates for producing acetate overlays that can be used on a visualiser, on an overhead projector or at a desk
  • electronic versions, using various dynamic geometry packages.

What does it do?

This unit:
  • uses acetate overlays or dynamic geometry tools to construct diagrams that help pupils use given facts to ‘build up’ derived geometrical properties
  • provides pupils with the language to articulate their reasoning
  • supports pupils in moving from a verbal chain of reasoning to a concise written argument.

Why use it?

It is intended:
  • to strengthen pupils’ understanding and appreciation of rigorous mathematical argument
  • to develop pupils’ skills and confidence in deductive reasoning and geometrical proof.

What do I do now?

Read the teacher’s notes on using build-ups, on the following pages:

Download a PDF file describing the build-up activities:

Download the resources for the activities:
Electronic versions: