What is a bar model?
A bar model is a visual representation of a math problem. Bar models are taught as an important tool to solve problems.
When are bar models introduced?
Bar models are first used in grade 2, however work done in kindergarten and grade 1 prepare students for bar models.
What are the steps to using bar models to solve problems?
​Click here to see the steps to using bar models
What are different types of bar models?
Bar models are used to solve a variety of problems. Students learn about part-part-whole. If they have two parts, then they need to find the whole (by adding). If they have one part and the whole, then they need to find the other part (by subtracting).
ADDITION
For example: John has 15 cookies. Mary gives him 8 more cookies. How many does he have now?
Click here for one example for this addition problem.
SUBTRACTION (COMPARISON)
Bar models are used to show comparisons. For example: There are 12 cows and 7 sheep on a farm. How many more cows are there than sheep?
Click here for one example for this comparison problem.
MULTIPLICATION
When solving multiplication and division, students are taught to use bars that are the same size. For example: John has $5. Daryl has three times more money. How much money does Daryl have?
Click here for one example for this multiplication problem.
FRACTIONS
5/8 of the students in the school band play a brass instrument. Of the remaining students, 2/5 play percussion. The remainder of the students play a woodwind. If there are 120 students in the band, how many play each instrument?
Click here for one example for this fraction problem.
Where can I see more examples of bar models?
This document has a fairly thorough description of types of bar models:Types of Bar Models
Is there one right way to make a bar model?
No. There are often multiple ways of representing a problem with bar models.
What do bar models lead to?
Bar models are a precursor to algebra. They are a visual connection to algebraic equations. Look back at the multiplication example:
j = 5
d = 3j
substitute 5 for j to solve.