Did you know?
Making exact change is not necessary for transactions in the real world. Vending machines and stores just simply give change or ask for more. However, understanding how to make exact change can be challenging and fun. Finding combinations and knowing if you have found them all is one way to introduce probability concepts to young children. Organizing the solutions and understanding how previous solutions can lead to other solutions helps children learn about problem solving.
What you need
- Real or play coins (see attached document)
- Paper and pencil
What to do
- Use the coins to make a combination equal to 50 cents.
- Now, come up with a different way to make 50 cents.
- Organize your coins in some way to keep track of your solutions.
- How many different ways can you make 50 cents?
What to ask
- Can you figure out all the possible ways to make 50 cents? Why or why not?
- Is it possible to make 50 cents using exactly two coins? Four coins? Fifteen coins?
- How can you use one of the combinations you made to make another new combination?
- Which combinations can you use in a vending machine?
What’s next?
- Grab a handful of change. Do you think it is more or less than 50 cents? How do you know?
- Count the change. How close are you?
- Try to find coin combinations that equal higher amounts, like 75 cents or a dollar.