You will need a set of pennies to work with. It is easiest with 100 pennies but any number will work. You can start with the pennies and do all the counting at one time or use pennies found during a couple week period and add to your count every day. The activity can actually be done with any coin, but the reference material on this site is for United States Lincoln Head pennies.

Activity 1. - small group work

1. Sort the pennies by the year they were minted, which mean the year they were made. Pennies all have the mint year stamped just below the bust of Lincoln.
2. In a classroom it may be best to divide the pennies up. For instance if there are 20 students you could work in teams of two and give 10 pennies to each group.
3. Each group needs to separate the pennies by year. Place the pennies in stacks by year and place the stacks in order by year.
4. Count and record the number of pennies for each year. Since pennies stay in circulation for an average of 30 yrs, you will probably find pennies made from 1970 to 2001.
5. Each group should answer the questions below

Activity 2 - if the class started by dividing into smaller groups

1. If the class divided the full set of pennies among groups in the class, next combine the results of the groups.
2. Be careful to keep the pennies from each group in order and put all the pennies into one big group. When you are done you should have stacks for each year and the stacks should be in order from the early 1970's until 2002. Did you have any pennies made before 1970? There are some still in circulation but they are much less common.
3. For the complete set of all pennies now count and record the number of pennies for each year.
4. The whole class should now answer the questions below, this time using the numbers from the combined sets of pennies.

QUESTIONS: Record the answer to the questions you can answer

1. How many pennies are in your set?
2. What is the oldest penny in the set?
3. What is the newest penny in the set?
4. Which stack is the highest, because it has the most pennies?
5. Of all your years from oldest to youngest, which year is the middle? If they are in order, this should be the middle stack or you may have two stacks in the middle.
6. Divide the total number of pennies in half (example half of 100 equals 50), then starting with the oldest penny, find the penny which is the halfway point in the set (for 100 it is penny number 50 or 51).
7. Can you find an "average" for the set of pennies? Is it he middle penny? Send in your answer. You can ask for hints if you want to.
   

Share your results.

• When you have finished answering the questions and recording the results, go to the webform at http://lrs.ed.uiuc.edu/students/tsullivl/commoncents/submitcents.htm - and submit your findings.
• Be sure to identify which part of the U.S. your class from and check back later to see how your set of pennies compares with everyone else's.

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