What is the first step in calculating percent error?

Subtract the measured value from the exact known value.

In an experiment, the expected outcome was 50 grams of a substance. A scientist measured 55 grams. Was the percent error positive or negative, and what does this indicate?

Positive, indicating an unintended reaction or overestimation.

Name: Calculating Percent Error and Change
Author: Insta~Lesson

7th Grade · Math · 30 min

I can calculate percent error or percent change to describe the accuracy of estimates or measurements.

1
Percent error is used to show how close you are to being right when your values don't meet the mark in an experiment.
2
To calculate percent error, first subtract the measured value from the exact known value, then divide by the exact known value.
3
After dividing, the final step to find percent error is to multiply by 100.

We would love to help you present Insta~Lesson to your colleagues and administrators. Here are a few resources you can use:

A simple one-pager you can use to share Insta~Lesson.

Learn how Insta~Lesson makes life easier for teachers. This is a great resource to share at a staff meeting or PD!

Learn more about Insta~Lesson's dedicated supports for partner schools.