Solving Word Problems using Bar Models

03 September 2018


A key feature of think! Mathematics is its use of bar models to solve word problems.

In think! Mathematics, students progress from using concrete materials, to drawing the cubes, to drawing bar models to represent quantities.

Bar models are rectangles used to represent numbers and quantities. They are used to translate verbal or written information into pictorial representation and help to enhance the student’s ability to visualise the problem. Bar models are often seen as a bridge between the story and the abstract equation in the word problem as they help students to select the most suitable operation. This is in contrast to the Keyword Strategy, which sometimes misleads students to select the incorrect operation.

Take this for example:
The blue ribbon is 31 cm long.
The blue ribbon is 12 cm longer than the red ribbon.

Students who adopt the Keyword Strategy may see the word ‘longer’ and proceed to add the two numbers together to find the length of the red ribbon. However, if they use bar models to represent the length of the two ribbons, they will see that the blue ribbon is longer than the red ribbon. They will then choose to subtract instead of add, thus avoiding the common error made if they were to use the Keyword Strategy.

Bar models are also useful in the upper grades where students need to solve complex word problems involving larger numbers or more difficult topics, such as fractions, ratios and percentages.