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.

solution dividing multiplying decimals

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:

Error bar model dividing multiplying decimals

Instead Rey’s bar model should have 5 times the number of units:

Correct bar model dividing multiplying decimals

Free Worksheet

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