You might be wondering what McDonald’s has to do with mathematics and critical thinking. Recently I found a copy of the original McDonald’s price list dating back to the 1940s when McDonald’s was owned by the original founders, Dick and Mac McDonald. Since that time, the fast food franchise has become a global fast food brand recognised by most. It is because of this recognition that the 1940s menu makes a perfect stimulus for mathematical investigation and critical thinking. The links between mathematics and children’s lives are not always obvious for students, so opportunities such as this are important to ensure our students understand how mathematics can help to make important decisions that affect our finances, health and general wellbeing. Although you might consider rejecting this idea so as not to promote a fast food culture, consider this an opportunity for students to think critically about food choices.
The Maths and McDonald’s graphic below contains some suggestions for mathematical investigations and would best be suited to students in upper primary or lower secondary classrooms. However, they can be adapted quite easily for younger students.
Below, the prompts are listed in a table that details some of the potential mathematical content that students would be expected to apply, and the processes they would use in the application of the mathematics. Although not included in the table, the tasks also address several of the General Capabilities from the Australian Curriculum: Mathematics. In addition, the tasks lend themselves well to integration with other curriculum areas.
Investigation
Use Mathematics to: 
Mathematical Content

Processes (Working Mathematically components/Proficiencies) 
Notes

Investigate how prices have changed over time (comparing similar items)  · Addition
· Subtraction · Fractions (percentages) 
· Problem Solving
· Reasoning · Communicating · Fluency · Understanding 
· Provide access to Internet where possible to allow students to compare current prices
· Students could access census information to explore changes in cost of living 
Explore the popularity of McDonald’s food compared to other fast food options  · Statistics  · Reasoning
·Communicating ·Fluency ·Understanding 
· Students will need to spend time considering appropriate questions to ask
· Encourage students to analyse data and formulate conclusions resulting from the data 
Analyse the nutritional value of a McDonald’s meal compared to a typical home cooked meal  · Addition· Subtraction
· Multiplication· Division· Fractions 
· Problem Solving· Reasoning· Communicating· Fluency· Understanding  · The beauty of this investigation is that it is personalised. If students are working in groups, they will need to negotiate what a ‘typical’ home cooked meal is.
· Grocery store apps would be handy for this investigation if students have access to mobile devices · There are multiple ways this task could be completed 
Consider the cost of a McDonald’s meal for your family, compared to your favourite home cooked meal  · Addition
· Subtraction · Multiplication . Division · Fractions 
· Reasoning· Communicating· Fluency· Understanding  · The beauty of this investigation is that it is personalised. If students are working in groups, they will need to negotiate what a ‘typical’ home cooked meal is.
·Grocery store apps would be handy for this investigation if students have access to mobile devices· There are multiple ways this task could be completed 
Analyse the financial cost of eating takeaway compared to cooking the same food at home  · Addition
· Subtraction · Multiplication ·Division .Fractions 
· Problem Solving
· Reasoning · Communicating · Fluency · Understanding 
. The takeaway food considered in this task may not necessarily be McDonald’s.
. It is important to allow students to draw from personal experience to ensure they are engaged with the mathematics and the task. 
Using the Investigations in the Classroom
Once you have given students time to look at and discuss the original McDonald’s menu, you can choose to allow students to choose one or more of the investigations to explore. Better still, once they have completed an investigation they may be able to come up with one of their own – this is a great way to promote mathematical curiosity and wonder. Allow students to choose how they present their work, and encourage them to document all of the mathematics they do. It is also critical to build reflection into the investigation, so make sure you have some reflection prompts prepared for either verbal or written reflection.
The Maths and McDonald’s investigation provide opportunities for students to learn and apply mathematics in context. This improves student engagement, allows them to see the relevance of mathematics, promotes critical thinking and provides important and authentic assessment data.
The McDonald’s menu: https://www.thesun.co.uk/fabulous/food/3564107/mcdonaldsoriginalmenu1940firstever/