Finding Missing Parts Up to 5

Introduction

Welcome to our lesson on finding missing parts in part-part-whole relationships! In this lesson plan, we will apply part-part-relationships to finding missing parts up to 5. We'll start with concrete objects and scenarios before progressing to more abstract representations. By the end of the lesson, your learner will have developed the skills necessary to solve problems involving missing parts with confidence and proficiency.

Before beginning the lesson, your learner should be comfortable with subitizing 5 items (recognizing the amount without counting the items). They should also know how to partition numbers and show part-part-whole relationships.

Key Concepts

Once learners are fluent in identifying part-part-whole relationships of numbers, they can apply this skill to solve problems. This lesson focuses on finding the missing part of a part-part-whole relationship, which essentially involves subtracting a part from the whole. However, it's important to note that at this stage, there's no need to introduce subtraction vocabulary such as "take away" or "difference," nor do we need to use the subtraction symbol. These concepts will be introduced in future lessons as learners progress in their mathematical understanding.

Teaching Plan

The following activities will help your learner become confident in finding missing parts of numbers. Go through each activity using the number 5, then proceed to 4, 3, 2, and 1.

Examples and visuals to support the lesson:

1. Finding Missing Parts with Objects and Pictures

For this activity, provide your learner with scenarios where one of the parts is missing or unknown. Use a variety of representations, including concrete objects and pictures.

• Ask your learner to identify the missing part in each scenario. Encourage the development of reasoning skills by prompting them to explain their answers in full context. For example, they might say, "I know there were 5 candies in the jar. I see 2 on the table, so the other 3 are still in the jar."
• Ensure a diverse range of scenarios is included, such as situations where the known part is 0, where the missing part is 0, where the numbers represent measurements, and where the parts are not visually represented. For instance, you could say, "I am going to clap 5 times." After clapping one time, ask "How many more times do I need to clap?"
• Initially, display part-part-whole diagrams for added support. However, the ultimate goal is for your learner to solve the problems independently without relying on the diagrams.

Skill Check
I can use objects and pictures to find missing parts.

2. Diagrams with Missing Parts Up to 5

After your learner has gained confidence in finding missing parts using different contexts and scenarios, they can progress to more abstract representations.

• Begin by revisiting earlier scenarios and model them with cherry diagrams, encouraging your learner to use the diagram to justify and explain their answers.
• Next, introduce abstract number problems that are not associated with any specific context (no objects or pictures). Show them a cherry diagram with a number at the top and one number as the known part, and ask them to find the other number.
• If your learner encounters difficulty transitioning to abstract problems, provide counters or encourage them to use drawings to represent the problem.
• Prompt them to communicate their findings using words such as "part" and "whole." For example, they might say, "The whole is 5 and one part is two. So the other part must be three."

Skill Check
I can use cherry diagrams to find missing numbers.

Once your learner has completed a variety of problems using 5 as the whole, continue with 4, then 3, 2, and 1. Remember to start with concrete objects and pictures before transitioning to abstract number problems.

Additional Resources

Use these resources to support your learner's journey in finding missing numbers to 5:

• Part-Whole Cherry Models (mathsbot.com)

Summary

In this lesson plan, we explored finding missing parts up to 5 in part-part-whole relationships. We began by presenting learners with concrete scenarios and representations, gradually transitioning to more abstract problems. By revisiting earlier scenarios and modeling them with cherry diagrams, learners gained a deeper understanding of how to justify and explain their answers. As they progressed to abstract number problems, they applied their knowledge to solve problems without specific contexts or visuals. This gradual progression allows learners to build a solid foundation in finding missing parts in part-part-whole relationships, preparing them for more complex mathematical concepts in the future.

Reference: National Centre for Excellence in the Teaching of Mathematics