In this lesson plan, your learner will explore strategies for solving word problems that have three addends. They'll use various math tools such as part-whole models, story mats, and number lines to visualize addition with three numbers. These strategies will build a strong foundation for understanding more abstract math concepts.
Here are a few concepts that are helpful to know for the lesson:
Addends: Addends are the numbers that are added together to form a sum. For example, in 2 + 3 + 5 = 10, the numbers 2, 3, and 5 are the addends.
Part-Whole Scenarios: Part-whole scenarios involve partitioning a quantity into three parts. Previous lessons focused on partitioning into two parts; this lesson introduces scenarios with three parts, such as a group of marbles partitioned by color (e.g., 2 red, 3 blue, and 5 yellow marbles).
Joining Scenarios: Word problems that involve joining a quantity to another quantity are often presented with a first-then-now structure. In previous lessons, the stories had two addends (first and then). In this lesson, the stories will include three parts (first-then-then), representing the addition of three addends.
Teaching Plan
The following activities will help your learner become confident with solving problems involving three addends.
Examples and visuals to support the lesson:
1. Part-Whole Word Problems with Three Parts
Start with a word problem that has a part-whole structure with three parts, such as three groups of marbles or rolling three dice. If you use dice, use pictures rather than actual dice to avoid values that sum to greater than ten.
Include examples where one or more of the addends is zero. For example: "I have six yellow marbles, no blue marbles, and three red marbles. How many marbles do I have altogether?"
Use a stem sentence with the structure: "There are __, __, and __. Altogether there are __."
Skill Check
I can describe the whole and parts of word problems that involve adding three parts.
2. Part-Whole Models with Three Parts
Once your learner is confident with word problems and picture representations, introduce more abstract representations, including ten-frames and part-whole models (cherry or bar models).
Introduce the matching ten-frame or part-whole model alongside the word problem or picture. Then ask your learner to describe each number in full sentences.
For example: "The 2 represents the two red marbles." "The 3 represents the three blue marbles." "The 5 represents the five yellow marbles." "The 10 represents the total number of marbles."
Skill Check
I can describe the whole and parts of ten-frames and part-whole models that represent adding three parts.
3. Relating Stories, Models, and Equations
Encourage your learner to practice representing the scenarios different ways.
For example, give them a part-part-part-whole model and ask them to write a word problem to go with it. Or present an equation such as 10 = 6 + 3 + 1, and ask your learner to draw a part-part-part-whole model to represent it.
Make sure your learner is confident expressing equations with the equals symbol in different positions, for example: 10 = 2 + 3 + 5 and 2 + 3 + 5 = 10.
Skill Check
I can write equations to represent part-whole stories that have three addends.
4. Introducing First-Then-Then-Now Stories
Next, introduce word problems that involve joining quantities together. Include scenarios with three addends that sum to ten or less. Use a stem sentence with the structure: "First..., then..., then..., now..."
To help your learner understand the concept, model the story with concrete objects or pictures. Then, encourage your learner to connect the story with a more abstract representation. For example, demonstrate the addition sequence using ten-frames by adding the counters while you read the story problem.
Skill Check
I can use math tools to represent first-then-then-now stories that have addition with three numbers.
5. Practicing with Number Lines
Demonstrate the first-then-then-now stories on a number line by showing the two increases in quantity as two jumps on the number line. This representation will prepare your learner for bridging through ten in a future lesson.
Present a number line depicting two increases, along with a multiple-choice selection of equations. Ask your learner to select the correct equation and justify their choice.
Increase the challenge by asking your learner to write the equation from scratch or provide an equation and ask them to draw the corresponding number line.
Skill Check
I can use number lines to represent addition with three addends by taking two jumps on the number line.
Summary
By the end of this lesson plan, your learner will master addition with three numbers by solving a variety of problems that have three addends. They will use practical, pictorial, and abstract representations to solve addition problems, making math both engaging and intuitive.
With over 12 years of experience as a classroom teacher, tutor, and homeschool parent, my specialty is easing math anxiety for students of all ages. I'm committed to empowering parents to confidently support their children in math!
Skill Check