Missing Parts of Numbers 6 to 10

Introduction

In this lesson plan, we will apply part-part-relationships to finding missing parts of numbers 6 to 10. We'll start with concrete objects and pictures 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, laying the foundation for solving subtraction problems.

Before beginning the lesson, your learner should be fluent in finding missing parts up to 5.

Key Concepts for Missing Parts of Numbers 6 to 10

This lesson focuses on finding the missing part of a part-part-whole relationship, which essentially involves subtracting a part from the whole. 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 sign yet.

By now, your learner has most likely been working with part-part-whole relationships quite a bit and has developed confidence with partitioning numbers. This will help them apply more advanced reasoning skills to numbers 6 to 10 than when they worked with numbers up to 5. Here are a few concepts that may come up during the activities:

• Five and Some More: The numbers 6 to 10 can be described as "five and some more." For example, seven is "five and two more." This concept can help your learner find missing parts when one of the parts is five.
• Odd and Even: Understanding the relationships between odd and even numbers can help your learner determine if the missing number is odd or even. Here is a summary of the part-part-whole relationships for odd and even numbers:
  • If the whole is odd and one part is even, the other part must be odd.
  • If the whole is odd and one part is odd, the other part must be even.
  • If the whole is even and one part is odd, the other part must be odd.
  • If the whole is even and one part is even, the other part must be even.

Teaching Plan

The following activities will help your learner become confident in finding missing parts of numbers 6 to 10. Be sure to work at a pace that is comfortable for your learner.

Examples and visuals to support the lesson:

1. Exploring Missing Parts

For these activities, begin with number 6 and work up to 10. Spend several days reinforcing each number before progressing to the next number.

• Provide your learner with concrete or picture contexts where they should solve for the missing part for the number six. For example: "I have six counters. There are two counters in my open hand. How many counters are in my closed hand?"
• Encourage your learner to draw part-part-whole models that represent the contexts. For the previous example, they can draw a cherry model with 6 as the whole, 2 as a part, and a question mark to represent the missing part.
• Be sure to include scenarios where the known part or missing part is zero. Using the context of the previous example, you can say, "I have six counters. There are six counters in my open hand. How many counters are in my closed hand?"

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

2. Providing Variety

Providing a variety of contexts will deepen your learner's fluency in finding missing numbers. Here are some ideas:

• Include contexts that relate to measurements involving part-part-whole relationships. For example: A flower is six centimeters tall and a ladybird is three centimeters up the flower. How much further does the ladybug need to go to get to the top? In this context, 6 cm is the whole, 3 cm is a part, and the distance for the ladybug to get to the top is the missing part.
• Also, provide examples where the parts are not visual. For example: "I am going to clap four times." Clap once, then ask, "How many more times do I need to clap?"
• To increase the variety of contexts, encourage your learner to create their own scenarios using items they find around the house, at a playground, or on a nature walk.

Skill Check
I can use what I know about missing numbers to solve different kinds of math problems.

3. Building Connections

As you work through each number, take advantage of opportunities to build connections with other concepts. Here are a few examples:

• For contexts where 5 is one of the parts, encourage your learner to apply their understanding of numbers 6 to 10 as "five and some more." For example, if the whole is 7 and one of the parts is 5, your learner may say, "I know that seven is 5 and 2 more, so the missing number must be 2."
• Encourage your learner to apply what they learned about odd and even numbers to reason about the missing value. For example, if the whole is 8 and one of the parts is 6, your learner may say, "Since the whole is even and one of the parts is even, then the other part must be even."
• You're learner may also begin to recognize patterns with doubles. For example, if they know that doubling four is eight, they will know that when 8 is the whole and one of the parts is 4, the missing part is also 4.

Skill Check
I can use what I know about number patterns to solve missing number problems.

Once your learner has become fluent with finding missing parts of number six, repeat the activities for numbers 7, 8, 9, and 10. Keep in mind that as you progress to larger numbers, there will be an increasing number of combinations and it may take longer to complete the activities.

Additional Resources

Websites:

• Part-Whole Cherry Models (mathsbot.com) - set the maximum to 10.
• Bar Models (mathsbot.com) - set "max parts" to 2 and "whole" to 10.

Summary

In this lesson plan, we explored finding missing parts of numbers 6 to 10 using part-part-whole relationships. By providing your learner with a variety of contexts they will be able to apply these skills to many math concepts. Becoming fluent in identifying missing parts also prepares your learner for writing and solving subtraction problems.

Teaching Plan adapted from NCETM under OGL license v3.