Education Technology

# Activities

• ##### Subject Area

• Math: Elementary Math: Measurement
• Math: Elementary Math: Number Sense and Estimation
• Math: Middle Grades Math: Number Sense
• Math: Middle Grades Math: Problem Solving

K-5

60 Minutes

• ##### Device
• TI-15 Explorer™
• ##### Other Materials
This is Activity 7 from the EXPLORATIONS Book:
Developing Problem-Solving Skills with the TI-15

The following materials are required for this activity:
• Grocery store advertisements that show the cost of flour, sugar, and butter
• Recipe for Bonnie's Favorite Sugar Cookies
• Chart paper
• Markers

#### Activity Overview

Students will reduce a cafeteria recipe to suit a household recipe. They use compatible numbers to choose smaller measurements while retaining the original proportions.

#### Objectives

Students will explore the following concepts in this activity:

• proportional reasoning
• computation
• problem solving

As an introduction to the activity, pose the following situation to students:

You received a box of chocolates for Valentine’s Day. There are 35 chocolates in the box. You want them to last for two weeks, eating about the same number each day. How many chocolates can you eat each day?

Students will need to find ways to divide 35 chocolates to make 14 equal portions. Discuss possible ways to solve the problem,  since 35 is not evenly divisible by 14.

Following this example, students will use proportions to adjust a cookie recipe so t hat only have the amount of cookies are made. Finally, students will apply their problem solving skills to address the following problem:

The Problem: How much money can we make at a bake sale if we sell Bonnie’s Favorite Sugar Cookies?

Students will make a chart that shows the cost of the ingredients, three dozen cookies, the cost per cookie, and the profit for one batch of cookies. Team members will then provide explanations of the processes used to solve the problem.