In this lesson plan, your learner will explore addition equations with missing parts. By using various models including cherry diagrams, stories, and bar models, your learner will identify and solve for missing addends and sums.
There are two primary types of addition equations: part-part-whole equations and joining problems.
Part-Part-Whole: These equations are structured as part + part = whole. They involve breaking a quantity (whole) into two or more parts.
Joining Problems: Joining problems often follow an "if-then-now" format, where one action or event leads to another, resulting in a final total quantity.
Part-Part-Whole Equations
With part-part-whole equations, there are three common scenarios:
Unknown Whole: The parts (addends) are provided, and the total quantity (whole) is unknown. For example, 3 + 4 = whole.
Unknown Part: The total quantity (whole) and one part (addend) are provided, and the other part (addend) is unknown. For example, 8 + part = 12.
Both Parts Unknown: The total quantity (whole) is provided, and both parts (addends) are unknown. For example, part + part = 10.
This lesson will focus on part-part-whole equations that have an unknown whole or an unknown part.
Teaching Plan
The following activities will help your learner become confident in finding missing parts of addition equations.
Examples and visuals to support the lesson:
1. Part-Part-Whole Equations and Diagrams
In this activity, your learner will write addition equations that represent part-part-whole relationships.
Start by using concrete objects and pictures that clearly show two distinguishable parts. Ask your learner to represent the parts using a part-part-whole diagram (cherry or bar model) then find the sum.
Next, have your learner write the corresponding equations based on the part-part-whole diagram including the parts/addends and the whole/sum.
Encourage your learner to describe the context and equations using complete sentences, emphasizing the relationship between the parts/addends and the whole/sum.
Check your learner's understanding by asking them what each number in the equation represents, encouraging the use of vocabulary words such as addend and sum.
Once your learner is comfortable writing equations using concrete objects and diagrams, progress to using other math tools such as counters or multilink blocks.
Skill Check
I can write an addition equation that shows the parts and whole of a part-part-whole diagram.
2. Story Problems and Equations
This activity will reinforce your learner's understanding of part-part-whole relationships through a variety of tasks and story problems.
Story problems:
Provide your learner with story problems and/or part-part-whole diagrams with the whole missing. Give them a variety of tasks to complete based on the story problem or diagram. Examples include: identifying the correct equation from a list of equations, filling in equations with missing sums, and writing full equations from scratch.
Next, you can give your learner an equation and ask them to represent it using concrete objects or by drawing a picture, and then tell a story to go with the equation.
Remember to include examples where one of the addends is zero to reinforce understanding of the concept.
Additional tasks:
Provide true or false style questions that include incorrectly formatted equations. Examples include: 4 + 3 + 7; 7 = 4 = 3; 4 = 3 + 7. Have your learner describe why the equations are written incorrectly and make corrections.
Give your learner problems with three parts/addends and have them find the sum. For example: Fill in the missing number of 1 + 2 + 4 = ___ and draw a cherry model to represent the equation.
Skill Check
I can use stories, diagrams, and equations to find a missing whole or sum.
3. Addition Equations with Missing Parts
In this activity, your learner will transition from finding unknown sums to finding unknown parts of addition equations.
Begin by using structured representations that clearly show both parts, such as rows of double-sided counters alongside the equations.
Help your learner make connections to equations using visual aids, even if they can complete the equations using mental math. This will prepare them for solving more advanced problems in future lessons.
When your learner is ready, provide them with additional equations that have one of the parts missing. This time, encourage them to complete equations without the visual aids.
Skill Check
I can use math tools to find the value of any missing part of an addition equation.
4. Challenge Activity
Provide your learner with a challenge activity to promote deeper thinking. For example, show your learner an image of a balanced scale with a square on one side that weighs 10 and two circles on the other side. Ask your learner to find the weight of each circle and explain their reasoning.
Teaching your learner how to find missing parts of addition equations through the use of stories, cherry diagrams, and bar models is an engaging and effective approach. These models offer concrete visual representations that aid in reasoning and problem-solving. By providing diverse methods to explore and understand missing addends and sums, you can empower your learner to tackle math equations with confidence.
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Skill Check