Second Grade Math Warm-Ups: Week of April 4-8, 2016

We started a new unit this week on geometry, but aren’t all quite solid with adding and subtracting within 1000 yet, so we came back to that as well.

Monday

Somehow I got home today (it’s Friday, when I usually post these while I am eating pizza and watching our family movie) without a picture of Monday’s MWU.  Oh well, I’ll just tell you.  The chart simply asked the question “What is a polygon?”  Well, I thought it asked it simply, but I was surprised that many kiddos answered it very differently than I expected.  What I thought I was asking them to tell me was the definition of a polygon.  What most of them game me was a picture of a hexagon.  Those that didn’t draw a hexagon pretty much described one in a few words.  I was puzzled by their responses, but as has happened more than once with these problems, it was a great lesson in asking better questions.  Had I asked “What is the definition of a polygon?” or even “Use words to tell what you know about polygons,” it would have made more sense to them.  I guess I did get information that they knew that a hexagon was a polygon, and that they didn’t understand the word itself, too, so it wasn’t a total wash. LOL

Tuesday

This one was another attempt at a vocabulary question, and was based on responses to the pretest from our geometry unit.  We had a great conversation about the difference between these two things, and how one is for 2D shapes and the other is for 3D.  We got out the rectangular prism and a Power Polygon that was a square and looked at the differences.  Oh, and notice how they connected the word “difference” with comparison, and so many of them drew a Venn Diagram.  Nice work, Rm. 202 kiddos!

FullSizeRender 35-min

Thursday

This was a great day, because Ja’Mia and Ava volunteered to create our Math Warm-Up (like has happened with lots of things in our room lately!), so I told them to have a go.  They had to solve their problem, too, so that they would know if we got it right.  Unfortunately I changed the numbers just a teeny bit when I wrote it, but I do know I got the -18 part correct from their original problem.  Check it out:

FullSizeRender 25-min

Want to explain a couple of things on the chart, based on our conversation.  The 900 at the top is because we talked about how estimating the answer before we solve the problem is a way of helping us know if we’re right.  We knew that the 300 and 500 would be at least 800, but then since both of the numbers were so big, it would be closer to 900 than 800.  We decided that the 69 in 369 was screaming at us (do you hear it??) that we should compensate and make the problem easier so we moved 1 from the 532 and made 370+531.  Then we moved 30 over to the 370 to make 400 and added together the resulting numbers.  Once we got to 901 – 18, we remembered what we had learned about constant difference and knew that if we added the same thing to both numbers we could get the same answer with an easier problem–thus we did 903-20, which is super easier than subtracting 18.  I was impressed with their hard work and glad to see that so many of them could apply the strategies we’ve been practicing.

Friday

Today is a busy morning usually, because we do a Week-in-Review sheet that takes the place of the math warm-up.  Often we don’t even get to it, but I decided to try it as our right-back-from-recess activity and it worked pretty well.  We tried another one like yesterday’s but I changed the numbers a bit.

FullSizeRender 48-min

This one has many annotations, too.  Let me explain:

We had to have a quick explanation of the directions, as many of them thought I meant that they should use their calculator.   I just meant I wanted them to figure it out. 🙂  The 800 is our estimate, which we figured out by thinking about 500 + 400, but then realizing that 73 is about 100 so we subtracted that next.  The red words were a request for a reminder of the strategies we have learned (as well as a reminder that I still owe them an anchor chart!): Circle, Split, Add; Circle, Split, Add with a number line; splitting; a chart that we’d used during our investigation into the T-Shirt Factory (that is really a visual form of regrouping 10s/1s); and compensation (making an easier problem).  As we were deciding upon a strategy to try together, I reminded them that good mathematicians choose one based on what the numbers tell them, not based on their favorite or the one they know the best.  Kiddos decided that the numbers were telling them to subtract first, because they noticed that the 75 in 475 could help us subtract the 73.  Once we rearranged the numbers, we realized our problem was a SUPER easy addition problem.

On a side note, at our class meeting today, the topic of math came up and many kiddos marked it as their “trouble spot” with a red dot.

Screenshot 2016-04-08 19.21.49

Again I was puzzled by this (probably because I define trouble spots as places where our class has something to figure out together or areas/activity where our choices could use some reworking and they instead mark them as things that were hard for them to figure out), so I had them explain.  Many said that the warm-ups were hard this week because they had to both add and subtract in the same problem.  We came to the conclusion that it was probably “hard” because we still needed practice.  We also discussed that labeling something as “hard” can sometimes lead us to believe we can’t do it.  If our self-talk is always negative instead of saying “I just don’t get it YET”, that ends up being our reality because we’ve quit trying.  We agreed that I could give them just one operation in a problem and that they would work on positive self-talk as they tackled these tricky problems next week. Win/win. 🙂

 

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