# Moira’s Birthday - Primary

## Curriculum Goal

#### Primary: Number Sense

• Estimate the number of objects in collections of up to 200 and verify their estimates by counting.
• Round whole numbers to the nearest ten or hundred, in various contexts.

## Context

• Students practice estimation skills in the context of various birthday party scenarios.
• Students should be comfortable with rounding whole numbers based on context.

## Materials

• Book: Moira’s Birthday by Robert Munsch
• Jar of small items (e.g. pencils, erasers, beans)
• Appendix A (Slideshow)

## Lesson

Introduction:

• Prepare a jar of small items before starting the lesson (see materials).
• Show students the jar of items lesson and ask them to estimate the number of items in it. Ask what strategies they use for estimating quantities.
• Invite students to share their understanding of the word “estimation”.
• An estimate is a number that is reasonably close to the right answer. Estimation is a powerful tool for planning because it can help you quickly determine a numerical quantity that is close to the answer.
• Ask students the following questions to support their understanding of estimation.
• Have you ever estimated anything? What do we estimate? (e.g. costs, temperature, distances, amounts)
• Can you estimate the number of students in our class without counting?
• Ask students whether they have helped plan a party before. Potential discussion questions include:
• How many people were invited to the party?
• What type of food was served at the party?
• How much food do you estimate was needed for the party? (e.g., Can you estimate how many slices of pizza were needed for all the party guests?)
• Read Moira’s Birthday to the class.

Activity:

• After reading the story, inform students that they will be helping Moira plan a new birthday party.
• Students will work through different scenarios to help Moira plan her party. Present the slideshow (Appendix A) and read the scenario on the first slide.
• Suggest to students that they think about their answers before sharing, but should take too much time because the objective is to quickly estimate quantities.
• Read the “speaker notes” underneath the slides for potential responses.
• Work through the scenarios on each of the slides using the same procedure.

Conclusion:

• Discuss the various strategies that students used to estimate quantities. Ask students to share their new understandings of estimation as a tool for planning.

## Look Fors

• Are students able to quickly estimate quantities in real-life scenarios?
• Are students able to round whole numbers to the nearest ten or hundred?
• Do students justify their estimations using the real-life context of scenarios?

## Extension

• Ask students to create their own party scenarios and estimate the number of items required for each scenario.
• Challenge students to estimate the number of pizzas required for a class party.