Problem Solving Club
2025-06-07Food Trucks & Flexible Thinking: Routine vs Non-Routine Problems in Mathematics
Let's talk about two kinds of maths problems: routine and non-routine. The names sound simple, but the difference they make in your classroom is anything but.
🚚 Let's Start with a Food Truck
Introducing our very first Problem of the Week at Problem Solving Club:
The Problem:
Two food trucks are catering at a festival.
Truck A can serve lunch to 160 people in 4 hours.
Truck B can serve the same number in 2.5 hours.
If they work together at full speed, how long will it take to serve 160 people?
Have you tried it yet? Have your students? Shared your strategy?
This is a non-routine problem, it's unfamiliar, a bit puzzling, and most students won't instantly know what to do. That's the point.
Let's see what a routine version of the same context might look like:
Routine version:
Truck A serves 40 people per hour. How many people will it serve in 3 hours?
Truck B serves 64 people per hour. How many does it serve in 5 hours?
Here, students apply known procedures, multiplication, division, interpreting rates. These are still important skills, and we definitely want students to be fluent in them.
But in the non-routine version, those same skills are still needed, but students now need to:
• Decide how to begin
• Combine rates
• Model and test ideas
• Make sense of context
• Justify solutions
And if you take the thinking further…
Stretch it:
What if there are 200 people? What about 500? What's the cheapest way to do it if Truck A costs less per hour?
Now we need to find generalisations. Does our strategy for work for every situation? This is mathematical thinking!
As one of my favourite papers, Adding it up (2001) puts it…
""Routine problems are problems that the learner knows how to solve based on past experience. When confronted with a routine problem, the learner knows a correct solution method and is able to apply it. Routine problems require reproductive thinking; the learner needs only to reproduce and apply a known solution procedure. For example, finding the product of 567 and 46 is a routine problem for most adults because they know what to do and how to do it.
In contrast, nonroutine problems are problems for which the learner does not immediately know a usable solution method. Nonroutine problems require productive thinking because the learner needs to invent a way to understand and solve the problem.""
It's Not Just About the Answer
Here's what makes non-routine problems so powerful:
• They build flexibility – there's no single path to the solution, so students try things, revise, and learn from what doesn't work.
• They foster collaboration – students compare strategies and reasoning, see multiple ways of thinking, and learn to communicate ideas clearly.
• They spark curiosity – there's a bit of mystery and experimentation involved. The challenge becomes something to figure out, not just a question to answer.
And yes, students still need their routine skills to attempt these problems: unit rates, multiplication, division, proportional reasoning, time, etc. But the thinking they do with them is what makes the learning powerful.
Strategies students might use
When solving non-routine problems, you might see students:
• Draw a diagram
• Use guess and check
• Make a table
• Work backwards
• Look for patterns
• Simplify the numbers
• Act it out
There are many more. And often, students invent new ones and that's what makes non-routine problem solving so rich. At times you might see that one of these strategies are not used and need to do some explicit teaching after the problem to support them with a way forward.
So, next time you're designing a task, try giving it a little twist. Keep the skills but open up the thinking. You might be amazed what your students come up with!
Problem Solving Club ✨
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References
National Research Council. (2001). Adding It Up: Helping Children Learn Mathematics. Washington, DC: The National Academies Press. https://doi.org/10.17226/9822.
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