Chocolate Chip Cookie Investigation


Students are shown a bag of chocolate chip cookies with 1000 chips in every package written on the bag. They are challenged to determine if the company is using false advertising or not. They are to develop a plan to support their answer for the challenge. They are given the following restriction. They are not allowed to sample every cookie in the bag. Students will record their solution on paper and present it to the class along with their reasons on why they think it will be fairly reliable. (Cognitive synthesis, Affective responding, Psychomotor guided response)

Supporting Information

  1. The number of chips in a bag is a product of the number of chips in a cookie and the number of cookies in a bag.
  2. Multiplication is repeated addition.
  3. The number of chips is equal to the sum of chips in all the cookies.
  4. The number of chips is equal to the product of the mean number of chips in a cookie and the number of cookies in the bag.
  5. There is a mean number of chips in a cookie.
  6. A random selection has an equal number of chances of being selected as all other possible samples.
  7. A cookie is a random selection.
  8. Estimation can be done by visualizing parts of the whole and multiplying.

Student's views

  1. Every cookie has a very different amount of chocolate chips.
  2. Half a cookie will have less than half as many chocolate chips.
  3. Cookies in the center of the bag do not need to be counted.

Materials: One bag of chocolate chip cookies, marking pens, transparency, and calculators



  1. Put the students into groups of three.
  2. Show the students a bag of chocolate chip cookies and challenge them to brainstorm ways to determine if the number of chocolate chips in the bags is actually 1000 if each group was given only one cookie. Time limit six minutes.
  3. Organize the exploration so each group will have access to the materials needed.
  4. Have each group use a method to determine the number of chocolate chips, illustrate their method of arriving at their answer and prepare to share their reasoning.


  1. Have students share their solutions and illustrations.
  2. Have students discuss and ask questions.
  3. Have them find similarities and differences with solutions.


Have students create a research question to investigate that would use random sampling. Example: How many Chevy trucks pass a certain corner in a year? How many banana seeds in a banana?

Dr. Robert Sweetland's notes