Using positive and negative numbers in context

This lesson develops the concept of using directed numbers in the practical context of temperatures and temperature change. Particular attention is paid to the use of directed numbers on number lines to explore the structures:

• Starting temperature + Change in temperature = Final temperature
• Final temperature – Change in temperature = Starting temperature
• Final temperature – Starting temperature = Change in temperature

The initial activity presents a series of questions about change in temperature. A situation is described in words and students must choose the correct calculation to go with it.

The main collaborative activity involves matching temperatures in different parts of the world with calculation arrows. Some of the arrows are blank and students must complete them to finish the puzzle.

There are pre-lesson and post-lesson formative assessment tasks. Detailed teacher notes give suggestions on questioning and how to use the resources. Full solutions are given for each of the sections.

This is a concept development lesson from the Mathematics Assessment Resource Service, a collaboration between UC Berkeley and the Shell Centre team at the University of Nottingham. Further information on the collection is given here.