# 10 bar modelling mistakes and how to avoid them

Are you making these bar modelling mistakes? If so, don’t panic — they’re simple to put right. Here’s how to avoid the common pitfalls and become a bar modelling maestro.

It’s hard to teach maths in a primary classroom without coming across bar modelling. This is a powerful visualisation technique that supports the concrete-pictorial-abstract (CPA) approach to learning.

When using bar models, there are some pitfalls to watch out for. Here are the most common mistakes and how to avoid them.

You plan an amazing lesson and know bar models will be the perfect tool to use. But as you start teaching, you notice a sea of blank faces looking back at you.

Bar models take time to embed, and learners can easily forget them if they aren’t used systematically throughout your school.

Here’s how to join-up your bar model teaching:

• Talk to your maths coordinator about how bar models are used in different year groups
• Confirm that bar modelling appears in your maths policy, and ask if staff know how and when to use them
• Children in EYFS can first experience bar models by using concrete maths manipulatives such as multilink cubes and tens frames alongside concrete resources. This prepares them for bar modelling in KS1
• Don’t assume everyone feels confident with bar models. Share good practice in staff meetings. Ask for CPD maths training if you or your colleagues feel unsure

## You rushed into using bar models

It’s easy to move learners away from handling concrete resources before they fully understand a concept. They then get confused and struggle to apply their knowledge.

Here’s how to prepare learners for bar modelling:

• Show bar models alongside concrete resources. Explain how they both represent the same thing
• Plan how you will support learners as they move from concrete to pictorial representations. It will take time and you might need to move flexibly backwards and forwards between the CPA stages

## You haven’t modelled how to draw bar models

When you feel secure using bar models, it’s easy to forget how confusing they can be at first. If you aren’t spending time using them in class, chances are your pupils won’t use them in their own work.

Here are some tips for how to practise bar modelling:

• Display different bar models and talk about what they show
• Question your pupils to make sure they fully understand how to draw and use a bar model
• Practise drawing them with pupils so they can see how they work
• Use colours to make different sections of the bars stand out

## Bar models differ from teacher to teacher

If every teacher in your school draws bar models differently, it can be confusing for pupils.

Try these tips to improve consistency:

• Agree a standard way to draw bar models in your school and include it in your calculation policy
• Send examples of bar models home to parents and share them on your school website
• Create a poster to display in classrooms showing correct drawings of bar models
• Look for common errors in pupils’ work and address any misconceptions

## You forgot to practise first

You’re in a rush and have to wing it in the classroom. You try to draw a bar model but it goes horribly wrong. Your pupils are confused and you’re flustered.

Even teachers who have been using bar modelling for years make mistakes. Here’s how to build confidence:

• Take a few minutes before class to practise to make sure you know exactly how your bar model will look
• Make sure the example you’re planning to use is correct and will be helpful

## You thought bar models taught problem-solving skills

Like many teachers, you’ve ditched RUCSAC and moved onto bar modelling. However, you still find your class struggling with word problems.

Bar modelling is a wonderful visualisation tool, but you still need to show your learners how to use it to solve problems.

These tips can help:

• Display a bar model alongside a problem. Talk about what it shows
• Make changes to your bar model in real time so pupils can see what’s happening

## It’s the wrong type of bar model

Did you know there are different types of bar models? Part-whole (or part-part-whole) models, which show the relationship between numbers, are perfect for fractions and missing-number problems. Comparison bar models are best for problems that compare two or more amounts. Drawing the wrong one can make it harder to find the answer.

Here’s how to make sure you use the appropriate bar model:

• Take a few minutes before the lesson to decide which type of bar model you’ll need
• Look for language that indicates you need to compare amounts. This will help you identify problems where its best to use a comparative bar model
• Practise drawing different types of bar models until you’re familiar with them

## The bar models may be too complex

You want your bar models to be just the right degree of difficulty for your learners. So when you first introduce them, start with simple examples. As pupils become more familiar with bar models, you can increase their complexity.

Here are some tips for introducing bar models to your learners:

• Start by giving your class the solution. This will stop pupils clamouring for the answer and allow you to concentrate on demonstrating the bar model
• Increase the complexity of the questions rather than moving on to something completely new
• Start at a lower level than your pupils usually work at to make their first experience of bar models simple and straightforward

## You use bar models for everything

Bar models are wonderful. So wonderful, they’re the only thing you use when teaching your class.

But what happens when children face different representations in worksheets, assessments and exams?

Here are a few suggestions for how to expand your toolkit beyond bar models:

• Encourage your learners to draw and share different representations of the same problem
• Plan how you will use different visual representations throughout each unit of work

## You get stuck in the ‘pictorial’ stage

Bar models are so simple and effective, it’s tempting to never stop using them. But pictorial representations are not the end goal; we want learners to advance to the abstract stage.

Try these tips to move learners forward:

• Move flexibly back and forth through the CPA stages, especially when introducing a new concept
• Show an abstract representation next to a bar model
• Share the CPA stages with your class so they know the next steps

Bar modelling is a wonderful strategy for visualising maths and for supporting children as they move from concrete to abstract understanding. However, despite our best efforts, we sometimes get it wrong.

Many mistakes can be avoided by deciding as a staff how bar models will be used in your school. You can help by starting a discussion of how bar models are currently used, making sure they are taught systematically and creating an environment of shared understanding. A consistent approach will lead to better results.

## For the community, by the community

Maths — No Problem! Community Event Conference,
28 November at The Royal Society, London.

Helly Douglas