More about Bar Diagramming: Great Strategies to Teach In Guided Math Groups
Here are 5 good resources that teach you how to use bar diagramming to work out word problems. Pull your students in guided math groups and begin to teach them how to diagram out problems. Give each group problems that are appropriate for their learning level. They do this in Singapore, which has some of the highest math scores in the world. Bar diagramming gets students to focus on the relationships in the problem instead of just heading straight for an operation.
Resource 5 (good pdf on division in general and the first part discusses bar diagramming in particular)