## Proportional Reasoning

Proportional reasoning: Connections to ratio and proportionProportional Reasoning and Multiplicative Thinking Proportional reasoning as Fundamental to Numeracy Proportional Reasoning and the Mathematics Curriculum |
Proportional
reasoning is an essential component of the school mathematics curriculum. It is
more than being able to calculate ratio and proportional exercises or applying
formulae to rate situations. Proportional reasoning is about being able to make
comparisons between objects or quantities in a multiplicative rather than
additive way. That is, the comparison is described using terms such as: double,
half, three-times greater; rather than simply describing something as smaller
than, or bigger than.
Many topics within the school mathematics curriculum require proportional reasoning, including problem solving with fractions, decimals, percentages, scale, probability, trigonometry, measurement, place value, geometry of plane shapes, algebra. It is also fundamental to topics beyond the mathematics curriculum such as calculations for density, molarity, speed and acceleration, and force, in Science; interpreting timelines in History; mapping in Geography. Proportional reasoning is also fundamental to real-world and every-day situations, such as: - determining the better buy when 1 kg costs $3.50 and 1.5 kg costs $4.20
- sharing two chocolate bars between three people
- adjusting calculations of travel time at varying speeds
- determining if 4c per litre is better than a 5% discount on your petrol bill
- calculating the sale price when everything is 30% off
- drawing a plan of the school yard
The development of proportional reasoning is something that takes time. It is fostered by quality learning experiences in which students have opportunities to explore, discuss and experiment with proportion situations. A rich field of potential investigations that link science and mathematics opens up when one considers the multi-faceted and multi-dimensional nature of proportional reasoning. |