Math in Our World: Money Bags

Emily and Eliza’s class collected coins all year to donate to local charities. They sorted them into bags by type and decided to give two bags to one charity and two bags to another. Eliza and Emily wanted the most money to go to the animal shelter.

A bag of pennies weighs 9,500 grams. A bag of nickels weighs 6,275 grams. A bag of dimes weighs 2,268 grams. A bag of quarters weighs 1,706.67 grams.

Eliza suggested the bags of pennies and nickels “because they are the heaviest.” Emily said, “We should give the bags of dimes and quarters to the animal shelter because dimes and quarters are worth more than nickels and pennies.”

The class did some research about coins and had quite a debate.

A chart showing the weight, thickness, and value in dollars of each coin. A penny weighs 2.500 grams, is 1.52 mm thick, and is worth 0.01 dollars. A nickel weighs 5.000 grams, is 1.95 mm thick, and is worth 0.05 of a dollar. A dime weighs 2.268 grams, is 1.35 mm thick, and is worth 0.10 dollars. A quarter weighs 5.670 grams, is 1.75 mm thick, and is worth 0.25 dollars.
  1. Use pictures, models, or numbers to show what is happening.
  2. What do you notice? What do you wonder?
  3. What mathematical questions can you ask about this situation? Answer all the questions you can!

Think about groups of 10 or 100. How much would 10 of each coin weigh? What is the value of 10 of each coin be? How about the weight and value of 100 of each coin?

  • Show your work to someone else, and explain your thinking. Did they understand?
  • Ask whether they have any other questions you can answer!

There’s another bag of coins that weighs about 12,000 grams. It isn’t sorted by type of coin. How much money could be in the bag? Show your work.