Bring in several jars of coins for your students to use for this activity. Place a jar on each table or break students into groups. Have them sort the coins based on where they were minted. There will either be a D for Denver, an S for San Francisco, or no mark indicates that it was minted in Philadelphia. Have your students make conclusions based on the numbers for each that they find. Are certain coins minted in certain places? Do the majority come from one city, or are the numbers pretty even?