Here’s a problem in 5th grade that involves all of the following:
- Problem Solving
- Bar Modeling
- Dividing Decimals
- Multiplying Decimals
Rey had 5 times as much money as James at first. When Rey gave James $12.50, both of them have the same amount of money. How much money does Rey have at first?
Solution
Here’s a solution using Bar Model.
A Note on Bar Modeling
Interpreting the problem in bar model heuristic is the first step to solve this problem. Often, students misunderstand the meaning of “5 times as much money as”. Thinking that 5 times means 5 units more in the bar model, they might draw:
Instead Rey’s bar model should have 5 times the number of units:
