standard_description: Solve word problems involving addition and subtraction of fractions referring to the same whole, including cases of unlike denominators, e.g., by using visual fraction models or equations to represent the problem. Use benchmark fractions and number sense of fractions to estimate mentally and assess the reasonableness of answers. For example, recognize an incorrect result 2/5 + 1/2 = 3/7, by observing that 3/7 < 1/2.
problem_activity: Narrative
The purpose of this activity is for students to solve a real-world problem that involves finding the volume of a figure composed of two right rectangular prisms. Unlike many other figures students have seen, this one can be decomposed into two rectangular prisms in only one way. Students may rearrange the two prisms to make a single, long rectangular prism.
Action and Expression: Develop Expression and Communication.
Give students access to graph paper or connecting cubes as tools to use to design their own garden.
Supports accessibility for: Visual-Spatial Processing, Conceptual Processing, Organization
Launch
Display the picture of the garden from the student workbook:
[IMG]
“This type of garden is called a raised bed garden because the plants are not in the ground.”
“If we planted a garden at our school, what vegetables would you want to grow?”
Activity
5 minutes: individual work time
5 minutes: partner discussion
Monitor for students who break the garden into two rectangular prisms, finding the volume of each, and for students who put them together to form a single rectangular prism.
Student Facing
The elementary school is going to build a raised bed garden like the one in the picture, but they will use a different design. Here is a diagram that shows the side lengths of the garden the school will build.
[IMG]
What is the volume of the garden? Explain or show your reasoning.
Write an expression to represent the volume of the garden.
[IMG]
Noah wants to design a garden with the same volume but different side lengths. What could the side lengths of his garden be?
Which garden design do you like better? Explain or show your reasoning.
Student Response
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Activity Synthesis
Display the diagram of the garden from the task.
Invite students to share how they found its volume.
“What do the two parts of the garden have in common?” (They are both 4 feet tall and 3 feet wide.)
“What is different about the two parts of the garden?” (The length. One piece is 10 feet long and the other piece is 8 feet long.)
“How could you put the pieces together to make a single rectangular prism?” (The sides that are 3 feet by 4 feet fit together and the length would be 18 feet.)


aligns: no