GUMMY WORMS [DAY 5]
SUBTRACTION
Uncover the various subtraction structures including removal, conparison, missing, addend, and missing subtrahend.
Intentionality
Math Talk
Spark Curiosity
Fuel Sensemaking
During Moves
Student Approaches
Consolidation
Purposeful Practice
Resources & Downloads
Educator Discussion Area
Intentionality & Unit Overview
Length of Unit: 5 Days
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Students will explore the final subtraction structure: missing addend.
Intentionality…
The purpose of the Day 5 activities is to reinforce the part-whole model from day 4 and to explore a new subtraction structure; missing addend. Students will engage in a math talk, investigate a new task and independently complete purposeful practice. Today’s learning serves to develop a deeper understanding of the following big ideas.
- Part-whole relations: Relationships between addition & subtraction.
- One-to-one correspondence.
- Measured and unmeasured comparison can be used to describe the relationship between two quantities
- One structure of subtraction is “missing subtrahend”.
- One structure of subtraction is “missing addend”.
Math Talk
Related String of Problems
Through the following math talk, students will be tasked with solving for unknown subtrahends. Students might consider using a concrete, pictorial or abstract part-whole model to make sense of the following number sentences. Once students make sense of the information, it is likely that many students will use a counting on strategy (reinforcing the relationship between addition and subtraction). Consider creating a context to help students visualize what is happening.
9 –
= 5
11 –
16 –
22 –
29 –
Spark Curiosity
Building On The Context Through Storytelling
Remind students of the context developed on Day 4, where there were gummy worms missing from the jar. For today’s task, you might also consider bringing back your jar of gummy worms and explaining today’s context orally.
As you know, I had a 17 gummy worms left in the jar yesterday after 8 were eaten. I went to the store last night and I bought more gummy worms, but now, there are 32 gummy worms in the jar. How many gummy worms did I buy last night?
Fuel Sense-making
Crafting A Productive Struggle: Prompt
Share the prompt with students:
If there were 14 gummy worms yesterday, and now there are 30, how many more did I buy?
Facilitator Notes
In this task, students will have an opportunity to reason through a subtraction scenario. This particular problem is an example of the “missing addend” subtraction structure. This task will allow students to apply a variety of strategies and models, while developing a deeper understanding of big ideas, specifically the following;
- Part-whole relations: Relationships between addition & subtraction.
- One structure of subtraction is “missing addend”.
During Moves
While Students Are Productively Struggling…
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Student Approaches
Student Approach #1: Concrete & Part Whole Model One-to-One
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Student Approach #2: Concrete & Part Whole Model Count 3 Times
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Student Approach #3: Number Path & Skip Counting By 2s
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Student Approach #4: Number Line & Friendly Numbers
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Consolidation
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Purposeful Practice
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Resources & Downloads
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Printable Lesson Plan PDF
Videos, Images & Media Files
Apple Keynote Presentation
Powerpoint Presentation
Printable Consolidation Prompts
Educator Discussion Area
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