Primary Type: Lesson Plan
Status: Published
This is a resource from CPALMS (www.cpalms.org) where all educators go for bright ideas!
Resource ID#: 46877
Marshmallow Math
In this lesson, students are physically engaged in measuring distances of tossed marshmallows to the nearest 1/2 foot. Using their measurements,
they will represent the data on a line plot and then solve word problems involving addition and subtraction of mixed numbers. This is a fun lesson that
motivates students to become excited about the difficult world of fractions.
Subject(s): Mathematics
Grade Level(s): 4
Intended Audience: Educators
Suggested Technology: Document Camera,
Computer for Presenter, LCD Projector
Instructional Time: 45 Minute(s)
Freely Available: Yes
Keywords: fractions, line plots, mixed numbers
Instructional Design Framework(s): Cooperative Learning
Resource Collection: CPALMS Lesson Plan Development Initiative
ATTACHMENTS
Formative Sample Line Plot.doc
Marshmallow Math Line Plot2.pdf
Marshmallow Math Summative.pdf
Sample Fraction Strips.JPG
LESSON CONTENT
Lesson Plan Template: General Lesson Plan
Learning Objectives: What should students know and be able to do as a result of this lesson?
As a result of this lesson, students should be able to:
Represent measurement data (to the nearest 1/2 foot) on a line plot.
Solve word problems based on data from a line plot.
Add and subtract mixed numbers with like denominators by converting whole numbers to mixed numbers.
Prior Knowledge: What prior knowledge should students have for this lesson?
Prior to this lesson, students should:
Be able to measure to the nearest 1/2 foot.
Understand that 1 foot equals 12 inches and 1/2 foot equals 6 inches.
Be able to represent and interpret data on a line plot.
Add and subtract fractions with like denominators.
Guiding Questions: What are the guiding questions for this lesson?
1. How does this equation match the word problem?
2. What does this number represent in the word problem?
3. What action is happening in the problem? What operation uses this action?
4. Think before you start doing. What will help you solve this problem?
page 1 of 4 5. How do you know your answer is correct? Explain your thinking.
Teaching Phase: How will the teacher present the concept or skill to students?
The following picture demonstrates how to set up the fraction strips for this portion of the lesson.
Teacher: I have two Snicker Bars in my desk. I have decided to give half of a Snicker Bar to one of you lucky students. I am wondering how much I will have left over
if I eat a whole one by myself.
Put two whole fraction strips on the board and write the number 2 next to them.
Teacher: What do I need to do one of the Snicker bars?
Students: responses
Teacher: What I am hearing is that I need to break one of the Snicker bars into two equal pieces.
Put one whole fraction strip on the board with two 1/2 fraction strips next to it and write the number 1 and the fraction 2/2 next to it.
Teacher: So now I have one whole Snickers and two halves of a Snicker. Does this still represent my original two Snicker bars?
Students: responses
Teacher: So, you are saying it is true that 2 is the same as 1 and two halves. Now for my original question, "Will I have any Snickers left over if I eat a whole one and
I give a half to one of you?" We know that we have 2 wholes or 1 and two halves. What do we need to do now?
Students: responses
Teacher: Okay, you are telling me that we need to find out how many Snicker bars will be eaten. If I eat a whole Snickers bar and one of you eats a half of one, how
many will we eat in total?
Students: responses
Teacher: So together we will eat 1 and 1/2 Snicker bars. Now we need to find out how much I will have left. What operation do we need to use to solve this problem?
Students: responses
Teacher: Alright, we are going to subtract. What two numbers are we going to subtract?
Students: responses
Discuss student responses. Make sure to clarify that 2 is the same as 1 and two halves. Discuss how it is easier to subtract mixed numbers and fractions with like
denominators. Set up the problem: 1 and 2 halves minus 1 and 1 half. Work through the problem and show the answer 1/2.
Teacher: Unfortunately, you will not be able to have a Snickers bar. However you will be having some marshmallows.
Guided Practice: What activities or exercises will the students complete with teacher guidance?
1. Students should be placed in groups of 5. Each student should be given 4 marshmallows. Let them eat one and save the rest for the activity. Each group should be
given a measuring tape that measures at least 25 feet. (Meter sticks or yard sticks can be used, but measurements will be less accurate and more time
consuming.) Place a copy of the Marshmallow Math Line Plot on a clipboard. Marshmallow Math Line Plot
2. Give the following instructions:
We will be going outside to throw marshmallows. The first person in your group will stand on the edge of the sidewalk and throw a marshmallow as far as you
can. Another person in your group will measure the distance of the throw to the nearest 1/2 foot. The person who throws the marshmallow will come and
mark his/her score on the line plot that I am holding on a clipboard. Every person in the group will take 2 turns throwing a marshmallow and 2 turns
measuring.
3. Rules:
1. Do not throw marshmallows at another person.
2. Use quiet outside voices.
page 2 of 4 3. If your marshmallow goes less than 5 feet, throw again.
4. When all groups are finished and data is recorded, return to the classroom and post the line plot using the document camera. Discuss data trends on the line plot
and ask Guiding Questions about the measurement process and data.
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the
lesson?
1. Students should be given the Marshmallow Math Worksheet and complete the questions independently using the data from the Marshmallow Math Line Plot on
display.
2. The teacher should circulate during this time and ask Guiding Questions to students. Ask students to explain their thinking. Students who struggle with math
concepts should be monitored closely and given support (see Accommodation Section). If needed, provide fraction strips and have students model their work.
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
1. For each of the questions, have a student come to the board and show how they solved the problem. Ask them to explain what strategies they used to solve the
problem. Ask another student to explain what that student just said. Ask if any students solved the problem using a different strategy and have them explain.
2. Give students the Summative Assessment (and any leftover marshmallows to enjoy).
Summative Assessment
Marshmallow Math Summative Assessment
1. To determine if students have mastered the learning objectives for this lesson, they should be able to fill in all 15 data points on the line plot. They should answer
both questions correctly and show their work. In quick student interviews, students should be able to explain the strategy they used to solve one of the problems.
2. The purpose of the summative assessment is to determine if students are able to correctly document data on a line plot and to use that data to solve word
problems that involve addition and subtraction of fractions and mixed numbers. This assessment also requires students to generalize skills from the marshmallow
math activity into other subject areas such as science.
Formative Assessment
1. In this lesson, the opening assessment will focus on interpreting data from a line plot and answering questions about the data. Students should answer questions in
unison using their fingers to represent their answers to the questions. Displaying the Formative Assessment Sample Line Plot using a computer and LCD projector.
Questions to ask:
How many students have 2 pets in their household? (1 pet, 3 pets, 4 pets, 5 pets)
How many pets per household is the most common? How do you know? (least common)
How many more students have 2 pets in their household than 5 pets? How do you know?
How many students either had 1 or 2 pets in their household? How do you know?
2. Periodically, ask students to explain the strategy used to get their answer. If 5 or more students miss a question, stop and clarify misconceptions and model the
problem on the board. Have an index card handy to write down the names of students who miss more than 2-3 questions. Plan to review line plots with them at a
later time.
Feedback to Students
1. During the activity, the teacher should be circulating throughout the room and asking students to describe their strategy for problem solving. The teacher should be
asking Guiding Questions and providing feedback to students throughout the process.
2. Students will receive feedback as to whether their answers are correct from their peers when students share their work on the board. They can compare their
results and reflect on their own reasoning process and findings.
ACCOMMODATIONS & RECOMMENDATIONS
Accommodations:
Students who have visual impairments or struggle with processing information on the board should be given preferential seating or a hard copy of the line plot.
Students with fine motor or mobility concerns should have peer assistance during the measuring portion of the lesson.
Students who are struggling with converting fractions should be given fraction strips (1 and 1/2) to use as a manipulative.
Extensions:
1. To extend this lesson, a copy of the line plot can be placed at a math center and students can create their own word problems based on the data. Students could
write their word problems on note cards (with answers on the back) and leave them as a challenge for other students to solve at the center. This extension
incorporates written language and writing conventions such as spelling, grammar and punctuation.
2. Also, this lesson could be incorporated in a science lesson. Students could identify and label different types leaves and measure them to the nearest 1/2 or 1/4 inch
and organize data on a line plot. Students could analyze data based on leave types and the teacher could write word problems for students to solve and explain.
Suggested Technology: Document Camera, Computer for Presenter, LCD Projector
Special Materials Needed:
Students:
Mini marshmallows-about 4-5 each (1 bag should be enough for an entire class)
Measuring tape (4-1 for each group)
Pencil/Paper
Student worksheet
Fraction strips (for students who need accommodations)
Teacher:
Clipboard (to hold line plot)
Document camera for display of line plot. (See Further Recommendations)
Computer and LCD projector or overhead
Further Recommendations: A computer with LCD projector can be used to display blank line plot on whiteboard and the teacher can quickly transfer the data
onto the whiteboard. The line plot could also be printed in poster size and students can put their data directly on the poster, which can be displayed.
page 3 of 4 Additional Information/Instructions
By Author/Submitter
This lesson also addresses the following Math Practice Standards:
MAFS.K12.MP.4.1 - Model with mathematics.
I would like to thank Stephanie Glaenzer for her help with this lesson.
SOURCE AND ACCESS INFORMATION
Contributed by: Jennifer Carlock
Name of Author/Source: Jennifer Carlock
District/Organization of Contributor(s): Volusia
Is this Resource freely Available? Yes
Access Privileges: Public
License: CPALMS License - no distribution - non commercial
Related Standards
Name
MAFS.4.MD.2.4:
MAFS.4.NF.2.3:
Description
Make a line plot to display a data set of measurements in fractions of a unit (1/2, 1/4, 1/8). Solve problems involving
addition and subtraction of fractions by using information presented in line plots. For example, from a line plot find and
interpret the difference in length between the longest and shortest specimens in an insect collection.
Understand a fraction a/b with a > 1 as a sum of fractions 1/b.
a. Understand addition and subtraction of fractions as joining and separating parts referring to the same whole.
b. Decompose a fraction into a sum of fractions with the same denominator in more than one way, recording each
decomposition by an equation. Justify decompositions, e.g., by using a visual fraction model. Examples: 3/8 = 1/8
+ 1/8 + 1/8 ; 3/8 = 1/8 + 2/8 ; 2 1/8 = 1 + 1 + 1/8 = 8/8 + 8/8 + 1/8.
c. Add and subtract mixed numbers with like denominators, e.g., by replacing each mixed number with an equivalent
fraction, and/or by using properties of operations and the relationship between addition and subtraction.
d. Solve word problems involving addition and subtraction of fractions referring to the same whole and having like
denominators, e.g., by using visual fraction models and equations to represent the problem.
Remarks/Examples:
Examples of Opportunities for In-Depth Focus
This standard represents an important step in the multi-grade progression for addition and subtraction of fractions.
Students extend their prior understanding of addition and subtraction to add and subtract fractions with like
denominators by thinking of adding or subtracting so many unit fractions.
Particular alignment to:
MAFS.4.NF.2.3c:
Add and subtract mixed numbers with like denominators, e.g., by replacing each mixed number with an equivalent
fraction, and/or by using properties of operations and the relationship between addition and subtraction.
page 4 of 4