Bar model method uses the concrete pictorial and abstract (CPA) sequence when teaching certain maths topics. The process starts by using real world, tangible representations, before moving onto showing the problem using a pictorial diagrams before then introducing the abstract algorithms and notations. The example below shows the concrete modelling with real objects, handling real objects and moving to the pictorial.
The bar model method is pictorial and it develops from children handling actual objects, to drawing pictures and then drawing boxes to represent objects. Eventually, they will no longer need to draw all the boxes, which represents individual units, instead they just draw one long bar and label it with a number. At this stage the bars do need to be somewhat proportional, so in the example above the purple bar representing 12 cookies is longer than the orange bar representing 8 cookies.
The particular power of the bar modelling pictorial approach is that it is applicable across a large number of topics. Once students have the basics of the approach secured, they can easily extend it across many topics.
A good understanding of the four operations is needed to use bar models. Children need to have strategies to add, subtract multiply and divide for them to use bar models. Bar models don’t give you an answer – it gives you an understanding of what to do do get to the answer. The what to do part is where children would normally use the four operations.