Error Detective Answer Key
About This Worksheet
This worksheet gives students incorrect scaling statements and asks them to find the mistake. Each problem shows a whole number multiplied by a fraction along with a claim about whether the result is larger, smaller, or equal to the original number. For example, 18 multiplied by ½ cannot be greater than 18 because multiplying by a fraction less than 1 makes a positive number smaller. This error-analysis format helps students think carefully about why scaling rules work.
Curriculum and Grade Alignment
This activity is written for fifth-grade math and supports CCSS.MATH.CONTENT.5.NF.B.5. Students should already understand how fractions less than, equal to, and greater than 1 affect positive quantities when used as scale factors. The next skill is explaining mathematical errors and using scaling ideas in more complex reasoning problems. This worksheet strengthens both conceptual understanding and mathematical communication.
Student Tasks
On this worksheet, students will study six incorrect statements about fraction multiplication and scaling. They identify what is wrong in each claim and then rewrite the statement correctly. The examples include fractions less than 1, greater than 1, and equal to 1. Students must use the value of the fraction to decide what should really happen to the starting number.
Common Challenges
Some students may correct the final comparison without explaining why the original statement was wrong. Others may calculate every product instead of using the scale factor to reason more quickly. Fractions greater than 1 can also cause confusion if students are more familiar with proper fractions. Teachers can help by having students first label the scale factor before they rewrite each statement.
Teaching Tips
This worksheet works especially well after students have had enough practice to begin explaining their own thinking. A teacher can model one error and show how to use the scale factor to prove the claim is incorrect. At home, parents can ask the child to pretend they are helping another student fix the mistake. That can make the explanation feel more natural and help reveal whether the child really understands scaling.
Worksheet Features
The worksheet includes six large response boxes with plenty of room for students to correct each statement. Every problem focuses on a different scaling claim, which keeps students from relying on one repeated pattern. The activity emphasizes reasoning rather than lengthy computation. It is a strong choice for review, small-group instruction, assessment, or deeper practice with fraction scaling.