Lost Buttons

In this lesson and the following one, students investigate subtraction more directly, beginning with the easier “take away” mode. They model “take away” subtraction with buttons and write subtraction sentences. This is lesson plan is good for the additive identity of zero. This also aids in teaching missing addends.

Weblink address (URL): 
Lost Buttons

Standards & Objectives

Learning objectives: 

Students will:

  • Determine the results of removing sets.
  • Review the term “difference.”
  • Investigate subtracting zero and subtracting all.
  • Find a missing addend.
Essential and guiding questions: 

What happens when we take away four buttons from seven buttons? Can you show that with these buttons? 

Which difference on our chart was the greatest? If we use only 10 buttons, do you think we could get a larger difference? How? 

What would be the smallest difference we could get with eight buttons? How would you get it? 

Suppose you had five buttons. What would the difference be if you lost two buttons? If you lost zero buttons? How about if you lost five buttons? 

Look at the chart we made. How did someone get a difference of five? Did anyone get a difference of five another way? 

Can you draw a picture to show that you had seven buttons and lost three of them? 

If you know there are seven buttons on a shirt and you can only see three of them, how many can’t you see? 

Show me how to use the Sums to 10 Chart to find the addend that’s missing when the sum is six and one addend is two.

Lesson Variations

Blooms taxonomy level: 
Analyzing

References

Contributors: 
Angela Hamilton
Originator: 
Ayers Institute for Learning & Innovation