## Estimate a Dinner Plate

### Barbara Johnson

#### Description

Students work with a partner to solve the real-world problem of planning a favorite meal given a specific budget. Estimation strategies are reviewed and practiced to help students determine the reasonableness of calculations in a given situation.

#### Objectives

The student writes notes, comments, and observations that reflect comprehension of content and experiences from a variety of media.

The student uses and justifies different estimation strategies in a real-world problem situation and determines the reasonableness of results of calculations in a given problem situation.

#### Materials

-Student copies and overhead transparency of Shopping List (See Associated File)
-Chart paper
-Pencil
-Paper
-Math journal

Materials for Workstation
-Computer(s) with Internet capability to access the Student Web Lesson, Let's Go Shopping (See Weblinks)

Materials for Summative Assessment
-Ads for toys, clothes, and other items marketed for kids
-Student copies of Shopping List (See Associated File)
-Pencil
-Paper
-Calculators

#### Preparations

1. Provide supermarket ads or circulars for the class.
2. Make a sample grocery list according to the items available in the supermarket ads to use in step 5 of the lesson procedures.
3. Make student copies and an overhead transparency of the Shopping List. (See Associated File)
4. Gather calculators for each student.
5. Check Internet connectivity for the Student Web Lesson, Let's Go Shopping. (See Weblinks)
6. Prepare materials for summative assessment activity.

#### Procedures

Background: Although this lesson is based on a birthday theme, it can be adapted to meet the needs of students who do not celebrate birthdays. In this case, the favorite meal could be planned as a “Back-to-School” celebration, and the personal money spent to buy school supplies.

GAIN ATTENTION
1. Ask students, “How are birthdays celebrated in your home?” Allow time for discussion and sharing.

2. Tell students, “In some homes, the birthday person is served his or her favorite meal and dessert. These meals are planned and prepared by the other family members.”

3. Explain to students that they will work with a partner to plan a favorite birthday meal using the prices and items found in supermarket circulars and ads.

PRESENT OBJECTIVES
4. Students make a shopping list (which includes the items and their prices) and then estimate how much money they need to pay the bill. Calculators are used to compare the actual cost of the meal with the estimate in order to determine the reasonableness of the calculation.

RELATE TO PRESENT KNOWLEDGE
5.Review the estimation process with students. List several items on the overhead or board and have students search the supermarket circulars for the advertised price. Model how to estimate the price of each item to the nearest dollar, and record estimates using an overhead transparency of the Shopping List. (See Associated File)

ENGAGE IN LEARNING
6. With the students, estimate the amount of money needed to pay the bill. Then use a calculator to find the exact amount of the bill. Compare estimates with actual cost and ask, “Is the calculated cost a reasonable amount based on the estimate?” Explain that calculators are not always right because we often enter information incorrectly. By estimating the answer the calculator is going to give us, it helps us check the reasonableness of the calculation.

7. List a few strategies students can use to keep the cost of the meals within the budget on the bottom part of the Shopping List transparency. (For example, “After every buy, I keep an estimated subtotal in my mind so I know how much money I still have to spend.”)

8. Discuss a reasonable budget for a meal. Set budget amount (i.e., \$25) before allowing students to work together on their own meal.

9. Make sure students have a copy of the Shopping List (See Associated File) and know the amount of money they may spend on the meal. Allow students time to work with their partners to plan their favorite meals. Circulate among students to offer guidance and clarify understanding.

10. As students finish, have them swap Shopping Lists to check estimates and actual costs. Any calculation errors should be addressed and corrected at this time.

11. Debrief the estimation process as a whole class. Discuss the reasonableness of the calculated cost based on the estimated amounts. Make a combined list of hints and strategies students used to keep the cost of their meals within the budget. Display these ideas on chart paper for future reference.

12. In their math journals, have students explain the estimation strategies or hint(s) they used to keep the cost of their meals within the budget.

PROVIDE OPPORTUNITY FOR PRACTICE
The following workstation may be incorporated during center time. Allow enough time for students to complete the workstation before formally assessing students' estimation strategies in real-world situations.

Workstation
13. Allow students to complete Let's Go Shopping, a Student Web Lesson. (See Weblinks) This lesson gives students the opportunity to practice rounding to the nearest dollar. It will take 10-15 minutes to complete.

14. When finished, students should list in their math journals any new hints or estimation strategies they learned and used in the online lesson.

#### Assessments

FORMATIVE ASSESSMENT
1. Review students' math journals for notes, comments, and observations that reflect a comprehension of using estimation strategies in real-world situations.
2. Monitor students' work while in partners to redirect misconceptions and misunderstandings when estimating amounts to the nearest dollar and to reteach.

SUMMATIVE ASSESSMENT
Description: Given a collection of ads, students complete a Shopping List of items they would buy if they were given \$50 for their birthday.

Criteria:
1. Items should be listed by price and estimated to the nearest dollar.
2. The list should contain an estimated cost which has been used to determine the reasonableness of the actual cost.
3. An explanation of the hints and strategies used to keep the cost of the items within the budgeted amount should also be included.

Students' math work and explanations should reflect adequate comprehension of how to use estimation strategies in real-world situations in order to determine the reasonableness of results of calculations in a given situation.

#### Extensions

Make daily menus for a family of four, using a grocery allowance for an entire week. Check the nutritional values of these meals by submitting them to Dole's Website at http://www.dole5aday.com.