Children's Museum of Houston

What you need

• Pretend cookies (or pictures of cookies) Plates
• Paper and pencils

What to do

1. Figure out how many plates the friends will have to buy for the bake sale if  they plan:
   • 2 dozen cookies with 3 cookies on each plate.
   • 5 dozen cookies with 4 cookies on each plate.
   • 8 dozen cookies with 5 cookies on each plate.
2. Figure out how many batches of cookies the three friends would need to bake for the bake sale. (Note: each batch makes 2 dozen cookies.)
   • 12 plates with 2 cookies on each plate.
   • 10 plates with 4 cookies on each plate.
   • 21 plates with 5 cookies on each plate.
   • 50 plates with 3 cookies on each plate.

What to ask

• Are there any cookies left over for snacks?
• Can you draw a model of how the cookies would be divided?
• Talk about the strategies used to figure out each question. Why does that one work best? Could you do it another way?
• If each cookie cost a quarter, how many plates of cookies would you need to sell to make $20.00?
• Is there a number of cookies per plate that will ALWAYS guarantee cookies leftover to eat?

Did you know?

What’s next?

• Talk about other situations where you would want to use division.
• Write a number sentence for each part of the activity.
• Look at number sentences to find an equation that would work no matter how many cookies and plates you had.
• Figure out how many batches each friend would have to bake using these rules:
  • Each friend has to make the same number of batches.
  • Each plate must have 5 cookies on it.
  • They have to use all of the cookies. (No eating extra cookies!)
  • There are 3 friends.
  • Each batch makes 2 dozen cookies.

To learn more

• A Remainder of One by Elinor J. Pinczes
• The Doorbell Rang by Pat Hutchins