Thank you, mother and father, for all of those diapers

This activity is currently being updated…. April 2026 - Stay tuned!

Which is a better deal, cloth or disposable diapers?  How much did you cost your parents in diapers?  In the future how much could your kid's diapers cost?   Help students realize all that mom and dad went through in buying and changing diapers. Students will compare the cost of buying disposable versus cloth diapers. They estimate how much they cost their parents in diapers and consider how much they will spend on diapers when they have a baby. This is a great math activity for Father’s Day or during the study of linear equations and introduction to systems of equations.

There is quite a bit of scaffolding built into the activity for students who might have limited experience with linear relationships and equation writing.  Depending on the experience of your students you might reduce the amount of work in the tables or omit some of the questions in this part of the lesson.

This activity gives the opportunity for students to engage in CCSS math practices 7 and 8 (see structure & express regularity in repeated reasoning).  As kids find diaper costs for various months, focus on what math they are doing over and over again, regardless of the time period.

If you would rather make this more of an open ended problem based learning task, simply give students the first page of the activity.  It has all the necessary info, but the path to determining the better deal will be more ambiguous.  By using the activity in this way, students can engage more in MP1, MP2 and MP4.  You can then go back and give some of the follow-up questions later separately.

The original activity was written by and shared with us by Andy Fehlner, 8th grade algebra teacher in Newton, MA. Thanks for sharing this timely activity with us, Mr. Fehlner!

Want to see student work?  The Blog: “Teaching Math Rocks” changed the title of the activity for High School students and they have provided student work samples.

The solution of this activity is available for all members.