Number Talks 3/ 15/2016

Every week I make an attempt to conduct a Number Talk (NT) with my Preservice Teacher Candidates (PSC). My goal is to experience math discourse so that they will be capable of implementing NT with their future students. This is a ritual I want my PCS to value not just to talk about math to insure students are getting the answer. I want my PCS to appreciate each other’s thinking and sense making of the mathematics being presented. This week I presented to problems involving addition with strategies.

52 +30

52 + 35

Here is the conversation for 52 +30:

Teacher: Who wants to defend 82? (I asked this question after everyone agrees the answer is 82). How did you get 82?

PSC 1: I visualized the hundreds chart.

Teacher: Wow! You are using your tools.

PSC 1: Yes. I knew going down is 10 more. I knew 52 +10 is 62. If I go down 10 more, 62+10 more is 72. So far I added 20. I need to add 10 more. 72 + 10 more is 82. So my answer is 82.

Teacher: Did anyone else solve this another way?

PSC 2: I used place value models in my head. I visualized 5 tens rods and 3tens and 2 ones. I added the tens rods and that will be 80. Then I added the 2 ones. 82.

Notice PSC are not stacking them up like the traditional US algorithm. I want my PSC to be able to embrace the tools of mathematics. Tools such as place value models or hundred charts are essential to learning mathematics conceptually. Mathematically proficient students use tools that are appropriate to their grade level and understand the tools limitations (Achieve the Core, 2016) .

Here is the conversation for 52 +35:

Teacher: Who wants to define 87?

PSC 3: I did the arrow method.

Teacher: Please explain.

PSC 3: I drew arrows from the 5 in 52 to the 3 in 35.

Teacher: Is that a 5 and a 3?

PSC 3: Yes that is a 5 and a 3

Teacher: Are you sure?

PSC 4: No, that is 50 and 30. She wants you to call it what it is.

PSC 3: Ok. I know. I drew an arrow from 50 to 30 and from 2 to 5. I added 50 + 30 that is 80. I added 2 +5 and that 7. The sum is 87.

I know this conversation seemed really picky and petty. However, students need to say the number represented correctly. If he said 5tens and 3 tens. I would have left it alone. However, it is highly important for students to know the correct terms especially as a preservice teacher. When students attend to precision “they calculate accurately and efficiently, express numerical answers with a degree of precision appropriate for the problem context. In the elementary grades, students give carefully formulated explanations to each other” (Achieve the Core, 2016)

I believe my preservice teachers are embracing other strategies instead of using the tradition US algorithm. They have grown as mathematically. I cannot wait until after Spring Break to find explore more mathematics with them.



References



Achieve the Core. (2016). Standards for Mathematical Practice. Retrieved from achievethecore.org: http://www.corestandards.org

Comments

  1. Claudia-Christian on a MissionMarch 19, 2016 at 8:28 PM

    My students' engagement in Numbers Talk is phenomenal. The conversations and sometimes debates gives me the reassurance that they are THINKING and using the strategies that have been taught.

    ReplyDelete
  2. Claudia-Christian on a MissionMarch 19, 2016 at 8:28 PM

    My students' engagement in Numbers Talk is phenomenal. The conversations and sometimes debates gives me the reassurance that they are THINKING and using the strategies that have been taught.

    ReplyDelete
  3. Dr Johanna MasseyMarch 19, 2016 at 10:03 PM

    I agree. I had to allow my students to conceptualize problems vs procedure thought. I was impressed because they were willing to use tools.

    ReplyDelete

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