Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Circle Graphs have my Students' Heads Spinning!
Name: Name
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993

I am currently in a teaching program. Last week I began a part of my practicum that has us teaching one lesson per week in the assigned school. My cooperating teacher asked me to introduce circle graphs to her sixth graders. She told me the students were familiar with the process of converting fractions to decimals and vice versa. One third of the way through my lesson, I realized the majority of the students had no concept of how to do this. I retaught the conversion process and then again had them look at circle graphs, yet they still remained confused. How can I better illustrate the circle graph concept and even the fraction to decimal conversion so my future students will understand? Any suggestions will be greatly appreciated. Thank you for your time, and I apologize for the lengthy scenario before my question.

I believe a circle graph is just a pie chart showing a fraction so a pie cut once through the middle demonstrates 1/2 = 0.5, etc. As for the fraction to decimal conversion, I cannot think of any methods other than the plain old fashioned long division. Of course, once you know that 1/8 = 0.125, then you know that 3/8 = 3 * 0.125 = 0.375 without having to do the long division. Hope this helps!

John Hawley

Hawley's hint about how to use 1/8 to get 3/8 is a nice use of pattern matching. But fundamentally, how will the students understand the "circle graph" idea? Basically, it is better to describe it as a pie chart because then students can visualize cutting it up just as if it were a pie. One way to get the concept across might be to cut up some cardboard "pies" into pieces; cut up one into thirds, one into fourths, fifths, eighths, and so forth...another would be to split up into groups of 5, hand each group a pie, and tell them to draw a piece of paper from a hat. One piece of paper would say 3/8 and the rest would say 1/8. Or, better yet, one could say 0.375 and the others 0.125. Then have them divide up the pie (or pizza) according to the numbers they drew. Hope this helps.


Click here to return to the Mathematics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory