When we think of measurement, we usually think about measuring physical quantities such as temperature or length. But every day, we use measures for many other ‘quantities’ such as the star rating for healthiness of food, GDP, BMI, biodiversity, social inequality or the infectivity of a disease. These are mathematical models, used to understand and make predictions about the world. Defining a measure mathematically enables data collection, identifying relationships to other variables and making predictions about the future. The Victorian Curriculum (Mathematics) 2.0 describes mathematical modelling as a key to informed and participatory citizenship. But this requires a fuller appreciation of mathematical modelling than applying known techniques to already mathematised situations. In this session, we consider examples of mathematical models commonly used in everyday life or science, examine what makes them good, and discuss how students can learn how experts and citizens can use these mathematical models to make good decisions.

Key takeaways:
1. Most people do not create mathematical models, but we all use them.
2. Mathematical models give us the best-known way to predict aspects of the future but might be wrong.
3. Understanding how mathematical modelling is used in society is an important outcome of learning mathematics.