Reflection: Discourse and Questioning Adding & Subtracting Mixed Numbers (Practice - Problem Solving) - Section 2: Launch/Guided Practice


This video used in the lesson is only 5 minutes, but it is very dense.  After the addition example, I stopped the clip and asked students to take a second and reflect on just how much work it is to solve one addition problem with mixed numbers.  I told them that they really should feel proud of themselves when they do all of this work.

Then I showed the rest of the clip.  

After the subtraction problem was solved on the clip, I was surprised to see a few students hands shoot right up, without my prompting them with questions.  

I called on these students to hear what they had to say. 

One student shared, they made this problem more difficult than they needed to.  The woman solving this problem could have recognized that 2/4 is equal to 1/2 and that is equal to 3/6.  If you knew this, then you could use 6ths as the denominator, not 12ths.  It would make the problem easier to work with.

Another student pointed out that even though the example showed that it takes many steps to solve a subtraction problem this problem was easier than the problems we have been solving, because it did not require regrouping.  You can take 2/12 from 6/12 without having to regroup the whole.

These observations are the rewarding results of building a classroom with student discourse and they show that the students were engaged in the learning process. 

Because of this feedback, I feel that I have chosen a good video clip to support this lesson.

  Observent Students
  Discourse and Questioning: Observent Students
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Adding & Subtracting Mixed Numbers (Practice - Problem Solving)

Unit 3: Adding and Subtracting Mixed Numbers
Lesson 9 of 11

Objective: SWBAT solve problems involving addition and subtraction of mixed numbers.

Big Idea: Students put their knowledge of adding and subtracting to use to solve problems.

  Print Lesson
Math, Fractions, Number Sense and Operations, problem solving, mixed numbers, models, Critical Area
  55 minutes
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